title: Is the config file .eslintrc deprecated in favor of .eslintrc.* files?
body: <p>I am updating some repos and would like to migrate from 5.x to 7.x eslint. But we use the file .eslintrc in all our repos. According to eslints's <a href="https://eslint.org/docs/user-guide/configuring#configuration-file-formats" rel="nofollow noreferrer">official configuration docs</a> it seems to be deprecated, now. What format should we use instead?</p>
  <p>I suppose <code>.eslintrc.js</code> format would be the most flexible while <code>.eslintrc.json</code> may be enough as long as we don't need any dynamic code? In the same configuration docs, the eslint team uses <code>.eslintrc</code> all the time by theirselves and I see the <code>.eslintrc</code> file a lot in other repos, too. So I am a little bit confused about how serious this deprecation really is, what is best practice, now, and what is most future proof.</p>