chore(ci): limit container job to master branch pushes

Author: nanotaboada

.github/workflows/python-app.yml

@@ -104,6 +104,7 @@ jobs:
   container:
     needs: coverage
     runs-on: ubuntu-latest
+    if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/master' }}
 
     permissions:
       contents: read
@@ -128,7 +129,10 @@ jobs:
         with:
           context: .
           push: true
+          platforms: linux/amd64
+          provenance: false
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
           tags: |
             ghcr.io/${{ github.repository }}:latest
-            ghcr.io/${{ github.repository }}:main
             ghcr.io/${{ github.repository }}:sha-${{ github.sha }}