[release] Update changelog with correct release date for 2.1.0

TBR=whesse@google.com

Change-Id: I37f041373f3902c4f03d770f87e52bdd129514b6
Reviewed-on: https://dart-review.googlesource.com/c/84635
Reviewed-by: Alexander Thomas <athom@google.com>
diff --git a/CHANGELOG.md b/CHANGELOG.md
index b984653..928d788 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,7 +24,7 @@
   for testing and it is no longer supported. `--categories=Server` continues to
   work at this time but it is deprecated, please use `--server-mode` instead.
 
-## 2.1.0 - 2018-10-31
+## 2.1.0 - 2018-11-15
 
 This is a minor version release. The team's focus was mostly on improving
 performance and stability after the large changes in Dart 2.0.0. Notable