Merge pull request #456 from remotemobprogramming/slack-badge

fix slack badge

README.md

@@ -12,7 +12,7 @@
     <img  alt="Downloads of latest" src="https://img.shields.io/github/downloads/remotemobprogramming/mob/latest/total" /></a>
   <a href="https://img.shields.io/github/stars/remotemobprogramming/mob">
     <img alt="Stars" src="https://img.shields.io/github/stars/remotemobprogramming/mob" /></a>
-  <a href="https://join.slack.com/t/mobsh/shared_invite/zt-2gxr4zvli-NnYvxvI32sjs9TjXUvnydA" rel="nofollow"><img src="https://camo.githubusercontent.com/5ade1fd1e76a6ab860802cdd2941fe2501e2ca2cb534e5d8968dbf864c13d33d/68747470733a2f2f696d672e736869656c64732e696f2f62616467652f736c61636b2d6a6f696e5f636861742d77686974652e7376673f6c6f676f3d736c61636b267374796c653d736f6369616c" alt="Slack Status" data-canonical-src="https://img.shields.io/badge/slack-join_chat-white.svg?logo=slack&amp;style=social" style="max-width: 100%;"></a>
+  <a href="https://join.slack.com/t/mobsh/shared_invite/zt-2gxr4zvli-NnYvxvI32sjs9TjXUvnydA" rel="nofollow"><img src="https://img.shields.io/badge/slack-join_chat-white.svg?logo=slack&amp;style=social" alt="Slack Status" data-canonical-src="https://img.shields.io/badge/slack-join_chat-white.svg?logo=slack&amp;style=social" style="max-width: 100%;"></a>
 </p>
 
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