title: fabric8 docker-maven-plugin: include additional tags on build
body: <p>I have the fabric8 docker-maven-plugin configured in my pom.xml as follows:</p>
  
  <pre><code>  &lt;build&gt;
      ...
      &lt;plugins&gt;
        ...
        &lt;plugin&gt;
          &lt;groupId&gt;io.fabric8&lt;/groupId&gt;
          &lt;artifactId&gt;docker-maven-plugin&lt;/artifactId&gt;
          &lt;version&gt;${docker.plugin.version}&lt;/version&gt;
          &lt;executions&gt;
            &lt;execution&gt;
              &lt;phase&gt;package&lt;/phase&gt;
              &lt;goals&gt;
                &lt;goal&gt;build&lt;/goal&gt;
              &lt;/goals&gt;
            &lt;/execution&gt;
          &lt;/executions&gt;
          &lt;configuration&gt;
            &lt;images&gt;
              &lt;image&gt;
                &lt;name&gt;${docker.image.prefix}/${project.artifactId}:%l&lt;/name&gt;
                &lt;build&gt;
                  &lt;dockerFile&gt;Dockerfile&lt;/dockerFile&gt;
                  &lt;assembly&gt;
                    &lt;descriptorRef&gt;artifact&lt;/descriptorRef&gt;
                  &lt;/assembly&gt;
                &lt;/build&gt;
              &lt;/image&gt;
            &lt;/images&gt;
          &lt;/configuration&gt;
        &lt;/plugin&gt;
        ...
      &lt;/plugins&gt;
      ...
    &lt;/build&gt;
  </code></pre>
  
  <p>I'm using the <code>%l</code> placeholder which tags the image with the <code>latest</code> label if the version contains <code>-SNAPSHOT</code>, otherwise it uses the pom version.
  When building from CI, I'd like to include some additional tags (possibly more then one) to my image (e.g. build number / branch name) but I'd like to keep <code>%l</code> placeholder behavior.
  I think that it should be possible using maven properties from command line, but I couldn't figure it out from the plugin docs (<a href="https://dmp.fabric8.io/" rel="nofollow noreferrer">https://dmp.fabric8.io/</a>)</p>
  
  <p>How can I include additional tags when executing the docker:build goal?</p>