Update actions/upload-artifact action to v6 (#214)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/build.yml

@@ -17,7 +17,7 @@ jobs:
       - name: Clean Build
         run: ./gradlew clean build
       - name: Archive Artifacts
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: Plot2Dynmap-SNAPSHOT
           path: build/libs/*-SNAPSHOT.jar