Only test python build on highest/lowest supported versions

Author: Luthaf

.github/workflows/tests.yml

@@ -48,7 +48,7 @@ jobs:
     name: check Python build
     strategy:
       matrix:
-        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11']
+        python-version: ['3.7', '3.11']
     steps:
       - uses: actions/checkout@v3