use python 3.9

Author: mgeier

.github/workflows/python-versions.yml

@@ -5,9 +5,9 @@ jobs:
     strategy:
       matrix:
         python-version:
-          - "3.7"
+          - "3.9"
           - "3.13"
-          - "pypy-3.7"
+          - "pypy-3.9"
           - "pypy-3.11"
     runs-on: ubuntu-22.04
     steps:
@@ -28,7 +28,6 @@ jobs:
       - name: Install Python package
         working-directory: git-repo
         run: |
-          python -m pip install --upgrade pip
           python -m pip install --group test .
       - name: Run tests
         run: |