docs: add karthik20 as a contributor (#438)

* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

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

Author: allcontributors[bot]

.all-contributorsrc

@@ -648,6 +648,15 @@
       "contributions": [
         "doc"
       ]
+    },
+    {
+      "login": "karthik20",
+      "name": "karthik20",
+      "avatar_url": "https://avatars2.githubusercontent.com/u/12153250?v=4",
+      "profile": "https://github.com/karthik20",
+      "contributions": [
+        "doc"
+      ]
     }
   ],
   "contributorsPerLine": 7,

README.md

@@ -126,6 +126,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
   </tr>
   <tr>
     <td align="center"><a href="http://manueldugue.de"><img src="https://avatars1.githubusercontent.com/u/894149?v=4" width="100px;" alt=""/><br /><sub><b>Manuel Dugué</b></sub></a><br /><a href="https://github.com/testing-library/testing-library-docs/commits?author=mdugue" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/karthik20"><img src="https://avatars2.githubusercontent.com/u/12153250?v=4" width="100px;" alt=""/><br /><sub><b>karthik20</b></sub></a><br /><a href="https://github.com/testing-library/testing-library-docs/commits?author=karthik20" title="Documentation">📖</a></td>
   </tr>
 </table>