Merge pull request webrtc#119 from anatolid/patch-3

Update index.md

Author: KaptenJansson

Diff for: release-notes/index.md

@@ -4,6 +4,7 @@ title: Chrome Report Notes
 permalink: /release-notes/
 crumb: Release Notes
 ---
+  * [M57 Release Notes](https://groups.google.com/d/msg/discuss-webrtc/xXjeKbW_JYI/LIXzVrKWCwAJ)
   * [M56 Release Notes](https://groups.google.com/d/msg/discuss-webrtc/DyeVS9IMTLc/1gUM7osoCwAJ)
   * [M55 Release Notes](https://groups.google.com/d/msg/discuss-webrtc/BqqFMSR6s1E/rlPYFD0NCQAJ)
   * [M54 Release Notes](https://groups.google.com/d/topic/discuss-webrtc/S5yex8rNIjA/discussion)