docs: add istateside as a contributor for code, test (#1024)

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

.all-contributorsrc

@@ -1424,6 +1424,16 @@
       "contributions": [
         "code"
       ]
+    },
+    {
+      "login": "istateside",
+      "name": "Kevin Fleischman",
+      "avatar_url": "https://avatars.githubusercontent.com/u/7245931?v=4",
+      "profile": "http://www.hawkeye.dog",
+      "contributions": [
+        "code",
+        "test"
+      ]
     }
   ],
   "repoHost": "https://github.com"

README.md

@@ -317,6 +317,7 @@ Thanks goes to these people ([emoji key][emojis]):
     <td align="center"><a href="https://github.com/G-Rath"><img src="https://avatars.githubusercontent.com/u/3151613?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Gareth Jones</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/commits?author=G-Rath" title="Code">💻</a> <a href="https://github.com/testing-library/dom-testing-library/commits?author=G-Rath" title="Tests">⚠️</a></td>
     <td align="center"><a href="https://github.com/riotrah"><img src="https://avatars.githubusercontent.com/u/22646419?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rayat Rahman</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/commits?author=riotrah" title="Code">💻</a></td>
     <td align="center"><a href="https://github.com/savcni01"><img src="https://avatars.githubusercontent.com/u/18025894?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Nik Savchenko</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/commits?author=savcni01" title="Code">💻</a></td>
+    <td align="center"><a href="http://www.hawkeye.dog"><img src="https://avatars.githubusercontent.com/u/7245931?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Kevin Fleischman</b></sub></a><br /><a href="https://github.com/testing-library/dom-testing-library/commits?author=istateside" title="Code">💻</a> <a href="https://github.com/testing-library/dom-testing-library/commits?author=istateside" title="Tests">⚠️</a></td>
   </tr>
 </table>