Add Python 3.12 support & fix CI (#350)

* Add py3.12 support

- CI
- tox
- requisite ignore for dateutil (at time of writing)
- changelog item

* Move pytest config into setup.cfg

* Fix datetime deprecation warning pattern

In pytest config -- using `datetime.datetime.utcfromtimestamp` is
important for matching correctly.

For some reason, the previous pattern (as well as the fixed one) works
under a local dev environment with 3.12.

.github/workflows/build.yaml

@@ -62,7 +62,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
-        py: ['3.8', '3.9', '3.10', '3.11']
+        py: ['3.8', '3.9', '3.10', '3.11', '3.12']
     name: "Run tests on ${{ matrix.os }}, py${{ matrix.py }}"
     runs-on: ${{ matrix.os }}
     steps:

CHANGELOG.rst

@@ -10,6 +10,8 @@ Unreleased
 
 .. vendor-insert-here
 
+- Add official support for Python 3.12
+
 0.27.1
 ------
 

setup.cfg

@@ -61,3 +61,9 @@ disallow_untyped_defs = true
 ignore_missing_imports = true
 warn_unreachable = true
 warn_no_return = true
+
+[tool:pytest]
+filterwarnings =
+    error
+    # dateutil has a Python 3.12 compatibility issue.
+    ignore:datetime\.datetime\.utcfromtimestamp\(\) is deprecated:DeprecationWarning

tox.ini

@@ -3,9 +3,9 @@ envlist =
     mypy
     cov_clean
     py38-mindeps
-    py{311,310,39,38}
+    py{312,311,310,39,38}
     py310-{notoml,tomli-format}
-    py{38,311}-{json5,pyjson5}
+    py{38,312}-{json5,pyjson5}
     cov
 skip_missing_interpreters = true
 minversion = 4.0.0
@@ -90,7 +90,3 @@ commands = python ./scripts/vendor-schemas.py
 [testenv:generate-hooks-config]
 description = "update autogenerated pre-commit hooks"
 commands = python ./scripts/generate-hooks-config.py
-
-[pytest]
-filterwarnings =
-    error