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

Author: renovate[bot]

.github/workflows/gradle.yml

@@ -31,7 +31,7 @@ jobs:
         command: ./gradlew clean build
 
     - name: Upload artifact
-      uses: actions/upload-artifact@v5
+      uses: actions/upload-artifact@v6
       with:
         name: AuthMeVelocity
         path: |-