build: Update actions/upload-artifact action to v2.3.1 (#66)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

Author: renovate[bot]

.github/workflows/build.yml

@@ -18,7 +18,7 @@ jobs:
       - name: Clean Build
         run: ./gradlew clean build
       - name: Archive Artifacts
-        uses: actions/upload-artifact@v2.2.4
+        uses: actions/upload-artifact@v2.3.1
         with:
           name: Plot2Dynmap-SNAPSHOT
           path: build/libs/*-SNAPSHOT.jar