docs: add greenkeeper[bot] as a contributor (#613)

* docs: update README.md [skip ci]

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

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

.all-contributorsrc

@@ -670,6 +670,16 @@
         "doc",
         "ideas"
       ]
+    },
+    {
+      "login": "greenkeeper[bot]",
+      "name": "greenkeeper[bot]",
+      "avatar_url": "https://avatars3.githubusercontent.com/in/505?v=4",
+      "profile": "https://github.com/apps/greenkeeper",
+      "contributions": [
+        "infra",
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 7,

README.md

@@ -594,6 +594,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
   </tr>
   <tr>
     <td align="center"><a href="https://brave.com/loo095"><img src="https://avatars0.githubusercontent.com/u/85355?v=4" width="100px;" alt=""/><br /><sub><b>Jon Stevens</b></sub></a><br /><a href="https://github.com/jaredpalmer/tsdx/commits?author=lookfirst" title="Documentation">📖</a> <a href="#ideas-lookfirst" title="Ideas, Planning, & Feedback">🤔</a></td>
+    <td align="center"><a href="https://github.com/apps/greenkeeper"><img src="https://avatars3.githubusercontent.com/in/505?v=4" width="100px;" alt=""/><br /><sub><b>greenkeeper[bot]</b></sub></a><br /><a href="#infra-greenkeeper[bot]" title="Infrastructure (Hosting, Build-Tools, etc)">🚇</a> <a href="https://github.com/jaredpalmer/tsdx/commits?author=greenkeeper[bot]" title="Code">💻</a></td>
   </tr>
 </table>