docs: add greg-el as a contributor

* docs: update README.md [skip ci]

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

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

Author: allcontributors[bot]

.all-contributorsrc

@@ -582,6 +582,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "greg-el",
+      "name": "Greg Leonard",
+      "avatar_url": "https://avatars3.githubusercontent.com/u/45019882?v=4",
+      "profile": "https://github.com/greg-el",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

README.md

@@ -1,6 +1,6 @@
 ![crab pet](https://i.imgur.com/LbZJgmm.gif)
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-62-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-63-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️ [![Build status](https://badge.buildkite.com/7af93d81dc522c67a1ec8e33ff5705861b1cb36360b774807f.svg)](https://buildkite.com/mokou/rustlings)
@@ -225,6 +225,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="http://www.jawaadmahmood.com"><img src="https://avatars3.githubusercontent.com/u/95606?v=4" width="100px;" alt=""/><br /><sub><b>Jawaad Mahmood</b></sub></a><br /><a href="#content-jmahmood" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/GaurangTandon"><img src="https://avatars1.githubusercontent.com/u/6308683?v=4" width="100px;" alt=""/><br /><sub><b>Gaurang Tandon</b></sub></a><br /><a href="#content-GaurangTandon" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/dev-cyprium"><img src="https://avatars1.githubusercontent.com/u/6002628?v=4" width="100px;" alt=""/><br /><sub><b>Stefan Kupresak</b></sub></a><br /><a href="#content-dev-cyprium" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/greg-el"><img src="https://avatars3.githubusercontent.com/u/45019882?v=4" width="100px;" alt=""/><br /><sub><b>Greg Leonard</b></sub></a><br /><a href="#content-greg-el" title="Content">🖋</a></td>
   </tr>
 </table>