jib maven gcr auth (circleci for env vars)

<plugin>
        <groupId>com.google.cloud.tools</groupId>
        <artifactId>jib-maven-plugin</artifactId>
        <configuration>
          <to>
            <image>gcr.io/xxx-catalogue/xxx-catalog-be:${project.version}</image>
            <auth>
              <username>_json_key</username>
              <password>${env.GCR_JSONKEY}</password>
            </auth>
          </to>
          <container>
            <jvmFlags>
              <jvmFlag>-Dgeronimo.metrics.jaxrs.activated=true</jvmFlag>
            </jvmFlags>
            <mainClass>xxx.catalogue.be.meecrowave.Application</mainClass>
            <args>
              <arg>some</arg>
              <arg>args</arg>
            </args>
            <ports>
              <port>9998</port>
            </ports>
          </container>
        </configuration>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>build</goal>
            </goals>
          </execution>
        </executions>
      </plugin>