ci: replace upload-coverage script with codecov github action

Same as what pytest does, hopefully will fix coverage upload failures.

Author: bluetech

Diff for: .github/workflows/main.yml

@@ -110,9 +110,12 @@ jobs:
 
     - name: Upload coverage
       if: matrix.use_coverage && github.repository == 'pytest-dev/pluggy'
-      env:
-        CODECOV_NAME: ${{ matrix.name }}
-      run: bash scripts/upload-coverage.sh -F GHA,${{ runner.os }}
+      uses: codecov/codecov-action@v4
+      continue-on-error: true
+      with:
+        fail_ci_if_error: true
+        files: ./coverage.xml
+        verbose: true
 
   deploy:
     if: github.event_name == 'push' && startsWith(github.event.ref, 'refs/tags') && github.repository == 'pytest-dev/pluggy'