docs: update README.md

Author: allcontributors[bot]

README.md

@@ -300,6 +300,7 @@ Thanks goes to these people ([emoji key][emojis]):
     <td align="center"><a href="https://github.com/romain-trotard"><img src="https://avatars0.githubusercontent.com/u/17161484?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Romain Trotard</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/commits?author=romain-trotard" title="Code">💻</a></td>
     <td align="center"><a href="http://www.thomasmarshall.com"><img src="https://avatars0.githubusercontent.com/u/770763?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Thomas Marshall</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/commits?author=thomasmarshall" title="Code">💻</a> <a href="https://github.com/testing-library/dom-testing-library/commits?author=thomasmarshall" title="Tests">⚠️</a></td>
     <td align="center"><a href="https://github.com/johnjesse"><img src="https://avatars1.githubusercontent.com/u/6839660?v=4?s=100" width="100px;" alt=""/><br /><sub><b>johnjessewood</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/issues?q=author%3Ajohnjesse" title="Bug reports">🐛</a> <a href="https://github.com/testing-library/dom-testing-library/commits?author=johnjesse" title="Code">💻</a></td>
+    <td align="center"><a href="https://codepen.io/ariperkkio/"><img src="https://avatars2.githubusercontent.com/u/14806298?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ari Perkkiö</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/issues?q=author%3AAriPerkkio" title="Bug reports">🐛</a> <a href="https://github.com/testing-library/dom-testing-library/commits?author=AriPerkkio" title="Code">💻</a></td>
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