Try uploading problem report

Author: kahgoh

.github/workflows/java.yml

@@ -24,6 +24,11 @@ jobs:
       - name: Check if tests compile cleanly with starter sources
         run: ./gradlew compileStarterTestJava --continue
         working-directory: exercises
+      - name: Upload the generated file as an artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: problem-report.html
+          path: exercises/build/reports/problems/problems-report.html
 
   lint:
     name: Lint Java files using Checkstyle