ci:run slim job for py3.9 only

Author: edro15

.github/workflows/ci.yml

@@ -39,10 +39,10 @@ jobs:
   slim-validate:
     name: SLIM Validation
     needs: bundle-app
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [ 3.7, 3.9 ]
+        python-version: [ 3.9 ]
     steps:
       - name: Download artifact
         uses: actions/download-artifact@v4