[CI/CD][Fix] Avoid mixing `master` and `dev`

- The `dev` images must be created from `dev`
- Coverage information should be from `dev`

.github/workflows/pythonapp.yml

@@ -91,6 +91,8 @@ jobs:
         # Important! empty directories are skipped!!!!
         path: output
     - name: Upload Coverage
+      # Don't mix stable coverage with development coverage
+      if: github.ref == 'refs/heads/dev'
       env:
         COVERALLS_REPO_TOKEN: ${{ secrets.COVERALLS_REPO_TOKEN }}
         COVERALLS_FLAG_NAME: ${{ matrix.ki_release }}_${{ matrix.w_tests }}
@@ -109,6 +111,8 @@ jobs:
     runs-on: ubuntu-latest
     container: setsoft/kicad_auto_test:ki6
     needs: test
+    # Don't mix stable coverage with development coverage
+    if: github.ref == 'refs/heads/dev'
 
     steps:
     - uses: actions/checkout@v2
@@ -167,6 +171,8 @@ jobs:
     permissions:
       packages: write
       contents: read
+    # Don't create `dev` images using the `master`
+    if: github.ref == 'refs/heads/dev'
 
     steps:
     - name: Check out the repo
@@ -211,6 +217,8 @@ jobs:
     permissions:
       packages: write
       contents: read
+    # Don't create `dev` images using the `master`
+    if: github.ref == 'refs/heads/dev'
 
     steps:
     - name: Check out the repo
@@ -255,6 +263,8 @@ jobs:
     name: Finish Coveralls
     needs: test
     runs-on: ubuntu-latest
+    # Don't mix stable coverage with development coverage
+    if: github.ref == 'refs/heads/dev'
     steps:
     - name: Finished
       env: