add regression testing with python 3.12 (#208)

Author: zingale

.github/workflows/regtest.yml

@@ -16,7 +16,7 @@ jobs:
 
     strategy:
       matrix:
-        python-version: ["3.9", "3.10", "3.11"]
+        python-version: ["3.9", "3.10", "3.11", "3.12"]
 
     steps:
       - uses: actions/checkout@v4