docs: add bigtreetech as a contributor for platform (#887)

* 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

@@ -204,6 +204,15 @@
         "bug",
         "platform"
       ]
+    },
+    {
+      "login": "bigtreetech",
+      "name": "BIGTREETECH",
+      "avatar_url": "https://avatars.githubusercontent.com/u/38851044?v=4",
+      "profile": "http://www.bigtree-tech.com",
+      "contributions": [
+        "platform"
+      ]
     }
   ],
   "contributorsPerLine": 7,

README.md

@@ -1,6 +1,6 @@
 <span align="left"><img src="https://github.com/luc-github/ESP3D/blob/2.1/images/ESP3D.png" width="200px"/></span><span align="left">Firmware for ESP8266/ESP8285  and ESP32 used with 3D printer</span>  
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-21-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-22-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 [<img src="https://img.shields.io/liberapay/patrons/ESP3D.svg?logo=liberapay">](https://liberapay.com/ESP3D)
 
@@ -187,6 +187,9 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
       <td align="center" valign="top" width="14.28%"><a href="https://github.com/disneysw"><img src="https://avatars.githubusercontent.com/u/10690321?v=4?s=100" width="100px;" alt="disneysw"/><br /><sub><b>disneysw</b></sub></a><br /><a href="#ideas-disneysw" title="Ideas, Planning, & Feedback">🤔</a></td>
       <td align="center" valign="top" width="14.28%"><a href="http://www.fysetc.com"><img src="https://avatars.githubusercontent.com/u/36067086?v=4?s=100" width="100px;" alt="FYSETC.COM"/><br /><sub><b>FYSETC.COM</b></sub></a><br /><a href="#financial-FYSETC" title="Financial">💵</a> <a href="https://github.com/luc-github/ESP3D/issues?q=author%3AFYSETC" title="Bug reports">🐛</a> <a href="#platform-FYSETC" title="Packaging/porting to new platform">📦</a></td>
     </tr>
+    <tr>
+      <td align="center" valign="top" width="14.28%"><a href="http://www.bigtree-tech.com"><img src="https://avatars.githubusercontent.com/u/38851044?v=4?s=100" width="100px;" alt="BIGTREETECH"/><br /><sub><b>BIGTREETECH</b></sub></a><br /><a href="#platform-bigtreetech" title="Packaging/porting to new platform">📦</a></td>
+    </tr>
   </tbody>
 </table>