Update examples in README (#1835)

* Update --generate-hashes example in README

The previous output had a trailing backslash on the last hash line;
while this is apparently valid for both pip-sync and pip install, IMHO
it looks like a bug, and it also doesn’t reflect what pip-compile
currently emits (as of version 6.12.3), so update the example.

This puts the hashes example out of sync with some of the other examples
in the README, but they weren’t all in sync before either (various
examples were already referencing Django 4, 3 or 2), so I hope that’s
not an issue.

* Refresh all pip-compile outputs in README

In one case (layered requirements), I had to add a constraint on the
django-debug-toolbar version because otherwise no solution was found by
the legacy resolver. (The backtracking resolver does find a solution,
but isn’t the default yet.) This should probably be revisited later,
ideally by someone more knowledgeable than me :)

README.rst

@@ -105,46 +105,42 @@ You can produce your pin files as easily as:
 
     $ pip-compile -o requirements.txt pyproject.toml
     #
-    # This file is autogenerated by pip-compile with python 3.10
-    # To update, run:
+    # This file is autogenerated by pip-compile with Python 3.10
+    # by the following command:
     #
     #    pip-compile --output-file=requirements.txt pyproject.toml
     #
-
-    asgiref==3.5.2
-       # via django
-    django==4.1
+    asgiref==3.6.0
+        # via django
+    django==4.1.7
         # via my-cool-django-app (pyproject.toml)
-    sqlparse==0.4.2
+    sqlparse==0.4.3
         # via django
 
     $ pip-compile --extra dev -o dev-requirements.txt pyproject.toml
     #
-    # This file is autogenerated by pip-compile with python 3.10
-    # To update, run:
+    # This file is autogenerated by pip-compile with Python 3.10
+    # by the following command:
     #
     #    pip-compile --extra=dev --output-file=dev-requirements.txt pyproject.toml
     #
-
-    asgiref==3.5.2
+    asgiref==3.6.0
         # via django
-    attrs==22.1.0
+    attrs==22.2.0
         # via pytest
-    django==4.1
+    django==4.1.7
         # via my-cool-django-app (pyproject.toml)
-    iniconfig==1.1.1
+    exceptiongroup==1.1.1
         # via pytest
-    packaging==21.3
+    iniconfig==2.0.0
         # via pytest
-    pluggy==1.0.0
+    packaging==23.0
         # via pytest
-    py==1.11.0
+    pluggy==1.0.0
         # via pytest
-    pyparsing==3.0.9
-        # via packaging
-    pytest==7.1.2
+    pytest==7.2.2
         # via my-cool-django-app (pyproject.toml)
-    sqlparse==0.4.2
+    sqlparse==0.4.3
         # via django
     tomli==2.0.1
         # via pytest
@@ -179,18 +175,16 @@ Now, run ``pip-compile requirements.in``:
 
     $ pip-compile requirements.in
     #
-    # This file is autogenerated by pip-compile
-    # To update, run:
+    # This file is autogenerated by pip-compile with Python 3.10
+    # by the following command:
     #
     #    pip-compile requirements.in
     #
-    asgiref==3.2.3
+    asgiref==3.6.0
         # via django
-    django==3.0.3
+    django==4.1.7
         # via -r requirements.in
-    pytz==2019.3
-        # via django
-    sqlparse==0.3.0
+    sqlparse==0.4.3
         # via django
 
 And it will produce your ``requirements.txt``, with all the Django dependencies
@@ -242,26 +236,22 @@ version 8.0, ``pip-compile`` offers ``--generate-hashes`` flag:
 
     $ pip-compile --generate-hashes requirements.in
     #
-    # This file is autogenerated by pip-compile
-    # To update, run:
+    # This file is autogenerated by pip-compile with Python 3.10
+    # by the following command:
     #
     #    pip-compile --generate-hashes requirements.in
     #
-    asgiref==3.2.3 \
-        --hash=sha256:7e06d934a7718bf3975acbf87780ba678957b87c7adc056f13b6215d610695a0 \
-        --hash=sha256:ea448f92fc35a0ef4b1508f53a04c4670255a3f33d22a81c8fc9c872036adbe5 \
+    asgiref==3.6.0 \
+        --hash=sha256:71e68008da809b957b7ee4b43dbccff33d1b23519fb8344e33f049897077afac \
+        --hash=sha256:9567dfe7bd8d3c8c892227827c41cce860b368104c3431da67a0c5a65a949506
         # via django
-    django==3.0.3 \
-        --hash=sha256:2f1ba1db8648484dd5c238fb62504777b7ad090c81c5f1fd8d5eb5ec21b5f283 \
-        --hash=sha256:c91c91a7ad6ef67a874a4f76f58ba534f9208412692a840e1d125eb5c279cb0a \
+    django==4.1.7 \
+        --hash=sha256:44f714b81c5f190d9d2ddad01a532fe502fa01c4cb8faf1d081f4264ed15dcd8 \
+        --hash=sha256:f2f431e75adc40039ace496ad3b9f17227022e8b11566f4b363da44c7e44761e
         # via -r requirements.in
-    pytz==2019.3 \
-        --hash=sha256:1c557d7d0e871de1f5ccd5833f60fb2550652da6be2693c1e02300743d21500d \
-        --hash=sha256:b02c06db6cf09c12dd25137e563b31700d3b80fcc4ad23abb7a315f2789819be \
-        # via django
-    sqlparse==0.3.0 \
-        --hash=sha256:40afe6b8d4b1117e7dff5504d7a8ce07d9a1b15aeeade8a2d10f130a834f8177 \
-        --hash=sha256:7c3dca29c022744e95b547e867cee89f4fce4373f3549ccd8797d8eb52cdb873 \
+    sqlparse==0.4.3 \
+        --hash=sha256:0323c0ec29cd52bceabc1b4d9d579e311f3e4961b98d174201d5622a23b85e34 \
+        --hash=sha256:69ca804846bb114d2ec380e4360a8a340db83f0ccf3afceeb1404df028f57268
         # via django
 
 Output File
@@ -306,18 +296,16 @@ generated at the top of requirements files by setting the
 
     $ CUSTOM_COMPILE_COMMAND="./pipcompilewrapper" pip-compile requirements.in
     #
-    # This file is autogenerated by pip-compile
-    # To update, run:
+    # This file is autogenerated by pip-compile with Python 3.10
+    # by the following command:
     #
     #    ./pipcompilewrapper
     #
-    asgiref==3.2.3
+    asgiref==3.6.0
         # via django
-    django==3.0.3
+    django==4.1.7
         # via -r requirements.in
-    pytz==2019.3
-        # via django
-    sqlparse==0.3.0
+    sqlparse==0.4.3
         # via django
 
 Workflow for layered requirements
@@ -344,22 +332,22 @@ selected for production in ``requirements.txt``.
 
     # dev-requirements.in
     -c requirements.txt
-    django-debug-toolbar
+    django-debug-toolbar<2.2
 
 First, compile ``requirements.txt`` as usual:
 
 .. code-block:: bash
 
     $ pip-compile
     #
-    # This file is autogenerated by pip-compile
-    # To update, run:
+    # This file is autogenerated by pip-compile with Python 3.10
+    # by the following command:
     #
     #    pip-compile
     #
     django==2.1.15
         # via -r requirements.in
-    pytz==2019.3
+    pytz==2023.3
         # via django
 
 
@@ -370,22 +358,22 @@ a constraint:
 
     $ pip-compile dev-requirements.in
     #
-    # This file is autogenerated by pip-compile
-    # To update, run:
+    # This file is autogenerated by pip-compile with Python 3.10
+    # by the following command:
     #
     #    pip-compile dev-requirements.in
     #
-    django-debug-toolbar==2.2
-        # via -r dev-requirements.in
     django==2.1.15
         # via
         #   -c requirements.txt
         #   django-debug-toolbar
-    pytz==2019.3
+    django-debug-toolbar==2.1
+        # via -r dev-requirements.in
+    pytz==2023.3
         # via
         #   -c requirements.txt
         #   django
-    sqlparse==0.3.0
+    sqlparse==0.4.3
         # via django-debug-toolbar
 
 As you can see above, even though a ``2.2`` release of Django is available, the