Update build.yml

Author: matsu1213

.github/workflows/build.yml

@@ -8,6 +8,7 @@ on:
     paths-ignore:
       - "**.md"
       - "renovate.json"
+  workflow_dispatch:
 
 jobs:
   build-test:
@@ -39,4 +40,9 @@ jobs:
 
       - run: java -version
       - run: mvn --version
-      - run: mvn -B package
+      - run: mvn -B package
+
+      - name: Upload a Build Artifact
+        uses: actions/upload-artifact@v3.1.0
+        with:
+          path: /home/runner/work/LeonGunWarNeoLobby/LeonGunWarNeoLobby/target/