docs: add gaearon as a contributor (#920)

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>

Author: allcontributors[bot]

.all-contributorsrc

@@ -1349,6 +1349,16 @@
       "contributions": [
         "bug"
       ]
+    },
+    {
+      "login": "gaearon",
+      "name": "Dan Abramov",
+      "avatar_url": "https://avatars.githubusercontent.com/u/810438?v=4",
+      "profile": "https://github.com/gaearon",
+      "contributions": [
+        "bug",
+        "review"
+      ]
     }
   ],
   "repoHost": "https://github.com"

README.md

@@ -307,6 +307,7 @@ Thanks goes to these people ([emoji key][emojis]):
     <td align="center"><a href="https://github.com/ph-fritsche"><img src="https://avatars.githubusercontent.com/u/39068198?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Philipp Fritsche</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/commits?author=ph-fritsche" title="Code">💻</a></td>
     <td align="center"><a href="https://medium.com/@renatoalencar"><img src="https://avatars.githubusercontent.com/u/6964593?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Renato Alencar</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/commits?author=renatoalencar" title="Code">💻</a> <a href="https://github.com/testing-library/dom-testing-library/commits?author=renatoalencar" title="Tests">⚠️</a></td>
     <td align="center"><a href="https://github.com/SimenB"><img src="https://avatars.githubusercontent.com/u/1404810?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Simen Bekkhus</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/issues?q=author%3ASimenB" title="Bug reports">🐛</a></td>
+    <td align="center"><a href="https://github.com/gaearon"><img src="https://avatars.githubusercontent.com/u/810438?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Dan Abramov</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/issues?q=author%3Agaearon" title="Bug reports">🐛</a> <a href="https://github.com/testing-library/dom-testing-library/pulls?q=is%3Apr+reviewed-by%3Agaearon" title="Reviewed Pull Requests">👀</a></td>
   </tr>
 </table>