docs: add the-ult as a contributor for maintenance (#262)

Author: allcontributors[bot]

.all-contributorsrc

@@ -195,7 +195,8 @@
       "avatar_url": "https://avatars.githubusercontent.com/u/4863062?v=4",
       "profile": "https://github.com/the-ult",
       "contributions": [
-        "code"
+        "code",
+        "maintenance"
       ]
     },
     {

README.md

@@ -207,7 +207,7 @@ Thanks goes to these people ([emoji key][emojis]):
     <td align="center"><a href="http://wwww.reibo.be"><img src="https://avatars1.githubusercontent.com/u/1673799?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Bo Vandersteene</b></sub></a><br /><a href="https://github.com/testing-library/angular-testing-library/commits?author=bovandersteene" title="Code">💻</a></td>
     <td align="center"><a href="https://github.com/jbchr"><img src="https://avatars1.githubusercontent.com/u/23141806?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Janek</b></sub></a><br /><a href="https://github.com/testing-library/angular-testing-library/commits?author=jbchr" title="Code">💻</a> <a href="https://github.com/testing-library/angular-testing-library/commits?author=jbchr" title="Tests">⚠️</a></td>
     <td align="center"><a href="https://github.com/GlebIrovich"><img src="https://avatars.githubusercontent.com/u/33176414?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Gleb Irovich</b></sub></a><br /><a href="https://github.com/testing-library/angular-testing-library/commits?author=GlebIrovich" title="Code">💻</a> <a href="https://github.com/testing-library/angular-testing-library/commits?author=GlebIrovich" title="Tests">⚠️</a></td>
-    <td align="center"><a href="https://github.com/the-ult"><img src="https://avatars.githubusercontent.com/u/4863062?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Arjen</b></sub></a><br /><a href="https://github.com/testing-library/angular-testing-library/commits?author=the-ult" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/the-ult"><img src="https://avatars.githubusercontent.com/u/4863062?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Arjen</b></sub></a><br /><a href="https://github.com/testing-library/angular-testing-library/commits?author=the-ult" title="Code">💻</a> <a href="#maintenance-the-ult" title="Maintenance">🚧</a></td>
     <td align="center"><a href="https://lacolaco.net"><img src="https://avatars.githubusercontent.com/u/1529180?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Suguru Inatomi</b></sub></a><br /><a href="https://github.com/testing-library/angular-testing-library/commits?author=lacolaco" title="Code">💻</a> <a href="#ideas-lacolaco" title="Ideas, Planning, & Feedback">🤔</a></td>
   </tr>
   <tr>