Fixed missing Python version

Python version hast to be set with v4 of the action. The version is now fixed to what is in Alpine 3.14.

Author: tobiasge

.github/workflows/push.yml

@@ -18,6 +18,8 @@ jobs:
         # Full git history is needed to get a proper list of changed files within `super-linter`
         fetch-depth: 0
     - uses: actions/setup-python@v4
+      with:
+        python-version: '3.9'
     - name: Lint Code Base
       uses: github/super-linter@v4
       env: