docs: add knpwrs as a contributor (#562)

* docs: update README.md

* docs: update .all-contributorsrc

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

Author: allcontributors[bot]

.all-contributorsrc

@@ -908,6 +908,15 @@
       "contributions": [
         "code"
       ]
+    },
+    {
+      "login": "knpwrs",
+      "name": "Ken Powers",
+      "avatar_url": "https://avatars0.githubusercontent.com/u/174864?v=4",
+      "profile": "https://knpw.rs",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "repoHost": "https://github.com"

README.md

@@ -250,6 +250,7 @@ Thanks goes to these people ([emoji key][emojis]):
   </tr>
   <tr>
     <td align="center"><a href="https://github.com/nstepien"><img src="https://avatars0.githubusercontent.com/u/567105?v=4" width="100px;" alt=""/><br /><sub><b>Nicolas Stepien</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/commits?author=nstepien" title="Code">💻</a></td>
+    <td align="center"><a href="https://knpw.rs"><img src="https://avatars0.githubusercontent.com/u/174864?v=4" width="100px;" alt=""/><br /><sub><b>Ken Powers</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/commits?author=knpwrs" title="Code">💻</a></td>
   </tr>
 </table>