title: Is it possible to have a dynamic strategy matrix in a workflow in GitHub Actions?
body: <p>I would like to specify a strategy matrix dynamically within the workflow. So, instead of:</p>
  <pre><code>strategy:
    matrix:
      foo: [bar, baz]
  </code></pre>
  <p>I want to first call some script which will compute and return an array such as <code>[bar, baz]</code> to me, and then I want to use that as the strategy matrix.</p>
  <p>Is this possible?</p>