Add GitHub follow button beneath v0.22 post

website/src/_posts/2017-12-0.22.md

@@ -162,3 +162,8 @@ Here is the full list of changes for version `0.22.0` (and patch `0.21.1`):
 - uppy-server: use typescript to compile code for a type safe servers (@ifedapoolarewaju)
 
 The Uppy Team
+
+<center>
+  <iframe src="https://ghbtns.com/github-btn.html?user=transloadit&repo=uppy&type=watch&count=true"
+  allowtransparency="true" frameborder="0" scrolling="0" width="100" height="20"></iframe>
+</center>