Use older ubuntu to get Python 3.7

Author: edgarrmondragon

.github/workflows/pythonpackage.yml

@@ -11,9 +11,12 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
+        os: [ubuntu-latest]
+        experimental: [false]
         include:
-        - experimental: false
+        - python-version: "3.7"
+          os: ubuntu-22.04
     continue-on-error: ${{ matrix.experimental }}
 
     steps: