Drop Python 3.5 support declaration, add Python 3.10 (#71)

.github/workflows/tests.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9, 3.10.0-beta.4]
+        python-version: [3.6, 3.7, 3.8, 3.9, 3.10.0-rc.1]
         os: [windows-latest, ubuntu-latest, macos-latest]
         arch: [x64, x86]
         exclude:

README.rst

@@ -12,7 +12,7 @@ An immutable mapping type for Python.
 The underlying datastructure is a Hash Array Mapped Trie (HAMT)
 used in Clojure, Scala, Haskell, and other functional languages.
 This implementation is used in CPython 3.7 in the ``contextvars``
-module (see `PEP 550 <https://www.python.org/dev/peps/pep-0550/>`_ and 
+module (see `PEP 550 <https://www.python.org/dev/peps/pep-0550/>`_ and
 `PEP 567 <https://www.python.org/dev/peps/pep-0567/>`_ for more details).
 
 Immutable mappings based on HAMT have O(log N) performance for both
@@ -30,7 +30,7 @@ copy-on-write approach (the benchmark code is available
 Installation
 ------------
 
-``immutables`` requires Python 3.5+ and is available on PyPI::
+``immutables`` requires Python 3.6+ and is available on PyPI::
 
     $ pip install immutables
 

immutables/__init__.py

@@ -2,10 +2,7 @@
 
 import sys
 
-if sys.version_info >= (3, 5, 2):
-    from typing import TYPE_CHECKING
-else:
-    from typing_extensions import TYPE_CHECKING
+from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     from ._map import Map

pyproject.toml

@@ -0,0 +1,6 @@
+[project]
+requires-python = ">=3.6"
+
+[build-system]
+requires = ["setuptools>=42", "wheel"]
+build-backend = "setuptools.build_meta"

setup.py

@@ -65,16 +65,16 @@
     version=VERSION,
     description='Immutable Collections',
     long_description=readme,
-    python_requires='>=3.5',
+    python_requires='>=3.6',
     classifiers=[
         'License :: OSI Approved :: Apache Software License',
         'Intended Audience :: Developers',
         'Programming Language :: Python :: 3 :: Only',
-        'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',
+        'Programming Language :: Python :: 3.10',
         'Operating System :: POSIX',
         'Operating System :: MacOS :: MacOS X',
         'Operating System :: Microsoft :: Windows',