docs: add xgbuils as a contributor (#444)

* docs: update README.md

* docs: update .all-contributorsrc

Author: allcontributors[bot]

.all-contributorsrc

@@ -784,6 +784,16 @@
         "test",
         "code"
       ]
+    },
+    {
+      "login": "xgbuils",
+      "name": "Xavier Garcia Buils",
+      "avatar_url": "https://avatars2.githubusercontent.com/u/6483614?v=4",
+      "profile": "https://twitter.com/xgbuils",
+      "contributions": [
+        "code",
+        "test"
+      ]
     }
   ],
   "repoHost": "https://github.com"

README.md

@@ -233,6 +233,7 @@ Thanks goes to these people ([emoji key][emojis]):
   <tr>
     <td align="center"><a href="https://aziz.js.org"><img src="https://avatars3.githubusercontent.com/u/17024120?v=4" width="100px;" alt=""/><br /><sub><b>Mohammad Aziz</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/commits?author=iAziz786" title="Code">💻</a> <a href="https://github.com/testing-library/dom-testing-library/commits?author=iAziz786" title="Tests">⚠️</a></td>
     <td align="center"><a href="https://www.linkedin.com/in/seetdev/"><img src="https://avatars2.githubusercontent.com/u/35116035?v=4" width="100px;" alt=""/><br /><sub><b>seetdev</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/commits?author=seetdev" title="Tests">⚠️</a> <a href="https://github.com/testing-library/dom-testing-library/commits?author=seetdev" title="Code">💻</a></td>
+    <td align="center"><a href="https://twitter.com/xgbuils"><img src="https://avatars2.githubusercontent.com/u/6483614?v=4" width="100px;" alt=""/><br /><sub><b>Xavier Garcia Buils</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/commits?author=xgbuils" title="Code">💻</a> <a href="https://github.com/testing-library/dom-testing-library/commits?author=xgbuils" title="Tests">⚠️</a></td>
   </tr>
 </table>