chore(deps): update actions/upload-artifact action to v6

Author: renovate[bot]

.github/workflows/maven.yml

@@ -25,7 +25,7 @@ jobs:
       - name: Build with Maven
         run: mvn -B package --file pom.xml
       - run: mkdir staging && cp target/*.jar staging
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: Package
           path: staging