docker-compose: remove maven package

docker-compose packages the jar automatically.
Jar release is no longer needed.

.github/workflows/maven.yml

@@ -36,13 +36,3 @@ jobs:
     - name: Publish Test Report
       if: success() || failure()
       uses: ScaCap/[email protected]
-
-    - name: Build with Maven
-      run: mvn -B package --file pom.xml
-
-    - name: Upload JAR
-      if: success()
-      uses: actions/upload-artifact@v2
-      with:
-        name: jchess-standalone-jar
-        path: target/jchess-jar-with-dependencies.jar