[release] Add release notes for 2.10.4

Change-Id: I0d3f79ecfa28292f46364b4a36c9fbc546e36a62
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/171583
Reviewed-by: Michael Thomsen <[email protected]>

Author: athomas

CHANGELOG.md

@@ -1,3 +1,12 @@
+## 2.10.4 - 2020-11-12
+
+This is a patch release that fixes a crash in the Dart VM (issues [#43941][],
+[flutter/flutter#43620][], and [Dart-Code/Dart-Code#2814][]).
+
+[#43941]: https://github.com/dart-lang/sdk/issues/43941
+[flutter/flutter#43620]: https://github.com/flutter/flutter/issues/43620
+[Dart-Code/Dart-Code#2814]: https://github.com/Dart-Code/Dart-Code/issues/2814
+
 ## 2.10.3 - 2020-10-29
 
 This is a patch release that fixes the following issues: