[SDK] Update changelog.

TESTS=no code changes

Change-Id: I32f92941963377b065a517c4153341addf61334d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/388240
Commit-Queue: Siva Annamalai <asiva@google.com>
Reviewed-by: Ben Konyi <bkonyi@google.com>

CHANGELOG.md

@@ -1,5 +1,14 @@
 ## 3.7.0
 
+###### Dart to Javascript Compiler (dart2js)
+
+- The dart2js compiler which is invoked when the command
+  'dart compile js' is used has been switched to use an AOT snapshot
+  instead of a JIT snapshot.
+
+[#53576]: https://github.com/dart-lang/sdk/issues/53576
+
+
 ## 3.6.0
 
 ### Language