[web-animations-1] Change Editor Brian Birtles to invited expert

Author: birtles

web-animations-1/Overview.bs

@@ -95,7 +95,7 @@ Group: csswg
 Repository: w3c/csswg-drafts
 Test Suite: https://github.com/web-platform-tests/wpt/tree/master/web-animations
 
-Editor: Brian Birtles 43194, Mozilla, bbirtles@mozilla.com
+Editor: Brian Birtles 43194, Invited Expert, brian@birchill.co.jp
 Editor: Robert Flack 98451, Google Inc, flackr@google.com
 Editor: Stephen McGruer 96463, Google Inc, smcgruer@google.com
 Editor: Antoine Quint 51377, Apple Inc, graouts@apple.com