docs: update CONTRIBUTORS (#829)

Author: ph-fritsche

.all-contributorsrc

@@ -1113,6 +1113,17 @@
         "review",
         "test"
       ]
+    },
+    {
+      "login": "Dennis273",
+      "name": "Dennis273",
+      "avatar_url": "https://avatars.githubusercontent.com/u/19815164?v=4",
+      "profile": "https://github.com/Dennis273",
+      "contributions": [
+        "bug",
+        "code",
+        "test"
+      ]
     }
   ],
   "commitConvention": "none",

CONTRIBUTORS.md

@@ -153,6 +153,7 @@ Thanks goes to these wonderful people ([emoji key][emojis]):
   <tr>
     <td align="center"><a href="https://matan.io/"><img src="https://avatars.githubusercontent.com/u/12711091?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Matan Borenkraout</b></sub></a><br /><a href="https://github.com/testing-library/user-event/commits?author=MatanBobi" title="Documentation">📖</a></td>
     <td align="center"><a href="https://kentcdodds.com/"><img src="https://avatars.githubusercontent.com/u/1500684?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Kent C. Dodds</b></sub></a><br /><a href="https://github.com/testing-library/user-event/commits?author=kentcdodds" title="Code">💻</a> <a href="#infra-kentcdodds" title="Infrastructure (Hosting, Build-Tools, etc)">🚇</a> <a href="#maintenance-kentcdodds" title="Maintenance">🚧</a> <a href="https://github.com/testing-library/user-event/pulls?q=is%3Apr+reviewed-by%3Akentcdodds" title="Reviewed Pull Requests">👀</a> <a href="https://github.com/testing-library/user-event/commits?author=kentcdodds" title="Tests">⚠️</a></td>
+    <td align="center"><a href="https://github.com/Dennis273"><img src="https://avatars.githubusercontent.com/u/19815164?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Dennis273</b></sub></a><br /><a href="https://github.com/testing-library/user-event/issues?q=author%3ADennis273" title="Bug reports">🐛</a> <a href="https://github.com/testing-library/user-event/commits?author=Dennis273" title="Code">💻</a> <a href="https://github.com/testing-library/user-event/commits?author=Dennis273" title="Tests">⚠️</a></td>
   </tr>
 </table>