docs: add samtsai as a contributor (#691)

* docs: update README.md

* docs: update .all-contributorsrc

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

.all-contributorsrc

@@ -1063,6 +1063,16 @@
       "contributions": [
         "doc"
       ]
+    },
+    {
+      "login": "samtsai",
+      "name": "Sam Tsai",
+      "avatar_url": "https://avatars0.githubusercontent.com/u/225526?v=4",
+      "profile": "https://github.com/samtsai",
+      "contributions": [
+        "code",
+        "test"
+      ]
     }
   ],
   "contributorsPerLine": 7,

README.md

@@ -535,6 +535,7 @@ Thanks goes to these people ([emoji key][emojis]):
     <td align="center"><a href="https://github.com/stevenfitzpatrick"><img src="https://avatars0.githubusercontent.com/u/23268855?v=4" width="100px;" alt=""/><br /><sub><b>Steven Fitzpatrick</b></sub></a><br /><a href="https://github.com/testing-library/react-testing-library/issues?q=author%3Astevenfitzpatrick" title="Bug reports">🐛</a></td>
     <td align="center"><a href="https://github.com/juangl"><img src="https://avatars0.githubusercontent.com/u/1887029?v=4" width="100px;" alt=""/><br /><sub><b>Juan Je García</b></sub></a><br /><a href="https://github.com/testing-library/react-testing-library/commits?author=juangl" title="Documentation">📖</a></td>
     <td align="center"><a href="https://ghuser.io/Ishaan28malik"><img src="https://avatars3.githubusercontent.com/u/27343592?v=4" width="100px;" alt=""/><br /><sub><b>Championrunner</b></sub></a><br /><a href="https://github.com/testing-library/react-testing-library/commits?author=Ishaan28malik" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/samtsai"><img src="https://avatars0.githubusercontent.com/u/225526?v=4" width="100px;" alt=""/><br /><sub><b>Sam Tsai</b></sub></a><br /><a href="https://github.com/testing-library/react-testing-library/commits?author=samtsai" title="Code">💻</a> <a href="https://github.com/testing-library/react-testing-library/commits?author=samtsai" title="Tests">⚠️</a></td>
   </tr>
 </table>