support python 3.12 (#47)

* add python 3.12 to CI test matrix
* update noxfile.py

Author: 2bndy5

.github/workflows/build.yml

@@ -167,6 +167,7 @@ jobs:
           - '3.9'
           - '3.10'
           - '3.11'
+          - '3.12'
         sphinx-version:
           - 'sphinx4'
           - 'sphinx5'

noxfile.py

@@ -1,6 +1,6 @@
 import nox
 
-SUPPORTED_PY_VER = list(f"3.{x}" for x in range(8, 12))
+SUPPORTED_PY_VER = list(f"3.{x}" for x in range(8, 13))
 nox.options.reuse_existing_virtualenvs = True