docs: update readme.md [skip ci]

Author: allcontributors[bot]

readme.md

@@ -1942,6 +1942,7 @@ Thanks goes to these wonderful people who have contributed to this repository!
   <tr>
     <td align="center"><a href="https://twitter.com/koooge"><img src="https://avatars2.githubusercontent.com/u/7419215?v=4" width="100px;" alt=""/><br /><sub><b>koooge</b></sub></a><br /><a href="#content-koooge" title="Content">🖋</a></td>
     <td align="center"><a href="https://twitter.com/michalbiesiada"><img src="https://avatars0.githubusercontent.com/u/18367606?v=4" width="100px;" alt=""/><br /><sub><b>Michal</b></sub></a><br /><a href="#content-mbiesiad" title="Content">🖋</a></td>
+    <td align="center"><a href="http://roywalker.me"><img src="https://avatars0.githubusercontent.com/u/611846?v=4" width="100px;" alt=""/><br /><sub><b>roywalker</b></sub></a><br /><a href="#content-roywalker" title="Content">🖋</a></td>
   </tr>
 </table>