Update .github/workflows/ci.yml

Author: martin-georgiev

.github/workflows/ci.yml

@@ -101,7 +101,7 @@ jobs:
       run: composer run-tests-with-clover
 
     - name: Upload coverage results to Coveralls
-      if: matrix.calculate-code-coverage == true && github.event_name == 'push'
+      if: matrix.calculate-code-coverage == true && github.event_name == 'pull_request'
       uses: coverallsapp/github-action@648a8eb78e6d50909eff900e4ec85cab4524a45b # v2
       with:
         github-token: ${{ secrets.GITHUB_TOKEN }}