Adds Python 3.12 to testing matrix

Author: tdstein

.github/workflows/main.yml

@@ -17,7 +17,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11']
+        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11', '3.12']
         include:
         - os: macos-latest
           python-version: '3.9'