Drop Python 3.7 and Sphinx 4 (#887)

Co-authored-by: Adam Turner <9087854+aa-turner@users.noreply.github.com>

.github/workflows/unit_tests.yml

@@ -7,33 +7,19 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.7', '3.8', '3.9', '3.10']
+        python-version:
+          - '3.8'
+          - '3.9'
+          - '3.10'
+          - '3.11'
+          - '3.12'
         sphinx-version:
-          - '4.0.3'
-          - '4.1.2'
-          - '4.2.0'
-          - '4.3.2'
-          - '4.5.0'
           - '5.0.2'
           - '5.1.1'
+          - '5.2.3'
           - '5.3.0'
           - '6.1.3'
           - git+https://github.com/sphinx-doc/sphinx.git@master
-        exclude:
-          # avoid bug in following configurations
-          # sphinx/util/typing.py:37: in <module>
-          #     from types import Union as types_Union
-          # ImportError: cannot import name 'Union' from 'types'
-          - python-version: '3.10'
-            sphinx-version: '4.0.3'
-          - python-version: '3.10'
-            sphinx-version: '4.1.2'
-
-          # Sphinx has removed support for Python 3.7, Breathe will follow.
-          - python-version: '3.7'
-            sphinx-version: git+https://github.com/sphinx-doc/sphinx.git@master
-          - python-version: '3.7'
-            sphinx-version: '6.1.3'
 
     steps:
       - uses: actions/checkout@v4

README.rst

@@ -98,7 +98,7 @@ branch.
 Requirements
 ------------
 
-Breathe requires Python 3.7+, Sphinx 4.0+ and Doxygen 1.8+.
+Breathe requires Python 3.8+, Sphinx 5.0+ and Doxygen 1.8+.
 
 Mailing List Archives
 ---------------------

pyproject.toml

@@ -14,7 +14,7 @@ urls.Documentation = "https://breathe.readthedocs.io/"
 urls.Homepage = "https://www.breathe-doc.org/"
 urls."Issue tracker" = "https://github.com/breathe-doc/breathe/issues"
 license.text = "BSD-3-Clause"
-requires-python = ">=3.7"
+requires-python = ">=3.8"
 
 # Classifiers list: https://pypi.org/classifiers/
 classifiers = [
@@ -30,7 +30,6 @@ classifiers = [
     "Programming Language :: Python",
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3 :: Only",
-    "Programming Language :: Python :: 3.7",
     "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
@@ -45,7 +44,7 @@ classifiers = [
     "Topic :: Utilities",
 ]
 dependencies = [
-    "Sphinx>=4.0,!=5.0.0",
+    "Sphinx>=5.0.2",
     "docutils>=0.12",
     "Jinja2>=2.7.3",
     "MarkupSafe>=0.23",