title: How to refactor deprecated set-env in github action
body: <p>I have a github action that runs set-env, now as it is deprecated as mentioned <a href="https://github.blog/changelog/2020-10-01-github-actions-deprecating-set-env-and-add-path-commands/" rel="nofollow noreferrer">here</a>, how can refactor the following code?</p>
  <pre><code> run: echo &quot;::set-env name=BRANCH_NAME::$(echo ${GITHUB_HEAD_REF} | tr -cd '[:alnum:]\n' | cut -c -30 | tr '[:upper:]' '[:lower:]')&quot;
  </code></pre>