Update actions/upload-artifact to v4

Signed-off-by: Alexander Brandes <mc.cache@web.de>

Author: NotMyFault

.github/workflows/build.yml

@@ -17,7 +17,7 @@ jobs:
       - name: Clean Build
         run: ./gradlew clean build
       - name: Archive Artifacts
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: Plot2Dynmap-SNAPSHOT
           path: build/libs/*-SNAPSHOT.jar