Add 3.12 to test matrix

Author: moomoohk

.github/workflows/tests.yml

@@ -70,7 +70,7 @@ jobs:
     strategy:
       matrix:
         # Match versions specified in tox.ini
-        python-version: ['3.8', '3.9', '3.10', '3.11', 'pypy-3.7']
+        python-version: ['3.8', '3.9', '3.10', '3.11', 'pypy-3.7', '3.12']
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps: