<plugin>
                <groupId>com.google.cloud.tools</groupId>
                <artifactId>appengine-maven-plugin</artifactId>
                <version>${appengine.maven.plugin.version}</version>
                <configuration>
                    <!-- https://cloud.google.com/appengine/docs/java/tools/maven-reference#appenginedeploy -->
                    <deploy.version>${app.version}</deploy.version>
                    <deploy.project>${app.id}</deploy.project>
                    <deploy.promote>False</deploy.promote>
                    <stage.enableJarClasses>true</stage.enableJarClasses>
                    <stage.stagingDirectory>${java.io.tmpdir}/appengine-staging</stage.stagingDirectory>
                </configuration>
            </plugin>