Changelog entry for UTF-8 breaking change
Changelog entry for UTF-8 breaking change

Closes https://github.com/dart-lang/sdk/issues/41100

Change-Id: I91b39af42cfc6c738056e20c1a96cad6fd3cfde6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/145785
Commit-Queue: Aske Simon Christensen <589eb3fd9a84f06d0ac46d3aa71dddcfb0814ccd@google.com>
Reviewed-by: Lasse R.H. Nielsen <80295e4ef244a07779f93eaa95d582bad8e316a5@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk