Replaced usages of the deprecated pkg_resources

(It seems like after the last commit added `python = 3.12` to `tox.ini`,
that version was actually being used, which made the tests fail against
Python 3.12-dev.)

As of Python 3.12, the `pkg_resources` package is no longer provided
(see https://docs.python.org/3.13/whatsnew/3.12.html#removed).
The package has been deprecated in favor of `importlib.metadata
(see the "Attention" notice at the top of
https://setuptools.pypa.io/en/latest/pkg_resources.html),
and the replacement for `pkg_resources.get_distribution()` is
`importlib.metadata.version()` (according to
googleapis/python-api-core#27 (comment)).
See also https://docs.python.org/3/library/importlib.metadata.html#distribution-versions.

docs/conf.py

@@ -12,7 +12,7 @@
 import os
 import sys
 
-from pkg_resources import get_distribution
+from importlib import metadata
 
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
@@ -48,7 +48,7 @@
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
-release = get_distribution("django-simple-history").version
+release = metadata.version("django-simple-history")
 # for example take major/minor
 version = ".".join(release.split(".")[:2])
 

simple_history/__init__.py

@@ -1,8 +1,8 @@
-from pkg_resources import DistributionNotFound, get_distribution
+from importlib import metadata
 
 try:
-    __version__ = get_distribution(__name__).version
-except DistributionNotFound:
+    __version__ = metadata.version(__name__)
+except metadata.PackageNotFoundError:
     # package is not installed
     pass