Fix CI workflow: Update upload-artifact from v3 to v4

- actions/upload-artifact@v3 is deprecated and causes workflow failures
- Update to v4 to fix the automatic failure in GitHub Actions

Author: gamma

.github/workflows/ci.yml

@@ -55,15 +55,15 @@ jobs:
 
       - name: Upload test results
         if: always()
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: test-results-java${{ matrix.java-version }}-gradle${{ matrix.gradle-version }}
           path: build/test-results/
           retention-days: 7
 
       - name: Upload build artifacts
         if: matrix.java-version == '17' && matrix.gradle-version == '9.2'
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: build-artifacts
           path: build/libs/*.jar