docs: add JonathanStoye as a contributor (testing-library#426)

* docs: update README.md [skip ci]

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


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

Author: allcontributors[bot]

.all-contributorsrc

@@ -238,7 +238,8 @@
       "avatar_url": "https://avatars2.githubusercontent.com/u/21689428?v=4",
       "profile": "http://jonathanstoye.de",
       "contributions": [
-        "doc"
+        "doc",
+        "code"
       ]
     },
     {
@@ -755,5 +756,6 @@
       ]
     }
   ],
-  "repoHost": "https://github.com"
+  "repoHost": "https://github.com",
+  "skipCi": true
 }