Try adding 3.12 back in

Author: wcarthur

.github/workflows/hazimp-tests.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ['3.8', '3.9', '3.10', '3.11']
+        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
     defaults:
       run:
         shell: bash -l {0}