See if python 3.7 still works when using an older Ubuntu version.

This should be undone once python 3.7 is EOL.

Author: Byron

.github/workflows/pythonpackage.yml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: ["ubuntu-latest", "macos-latest", "windows-latest"]
+        os: ["ubuntu-22.04", "macos-latest", "windows-latest"]
         python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
         exclude:
         - os: "macos-latest"