Add step to save coverage report in CI workflow

Signed-off-by: Rodrigo Nardi <[email protected]>

Author: RodrigoMNardi

.github/workflows/ruby.yml

@@ -104,7 +104,8 @@ jobs:
         if: always()          
 
       - name: Save coverage report
-        uses: actions/upload-artifact@3.1.2
+        uses: actions/upload-artifact@v4
         with:
           name: coverage-report
-          path: tmp/rspec_results.json
+          path: tmp/rspec_results.json
+          if-no-files-found: warn