title: Gitlab-ci: extend script section
body: <p>I have an <a href="https://gitlab.com/oriontvv/unity3d-gitlab-ci-example/pipelines/33877199" rel="noreferrer">unity ci-project</a>.
   <a href="https://gitlab.com/oriontvv/unity3d-gitlab-ci-example/blob/master/.gitlab-ci.yml" rel="noreferrer"><code>.gitlab-ci.yml</code></a> contains base <code>.build</code> job with one <code>script</code> command. Also I have multiple specified jobs for build each platform which extended base <code>.build</code>. I want to execute some platform-specific commands for android, so I have created separated job <code>generate-android-apk</code>. But if it's failing the pipeline will be failed too.(I know about <code>allow_failure</code>). Is it possible to extend <code>script</code> section between jobs without copy-pasting?</p>