Update CHANGELOG.md to reflect changes for version 2.1.5+1
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f26290f..ade93be 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 2.1.5+1
+
+- Cast stream to List<int> in 'readAsString', this is in preparation for
+  HttpClientResponse implementing Stream<Uint8List> (forward compatible
+  change, should be a no-op for existing usages)
+
 ## 2.1.5
 
 - Require at least Dart 2.0.0-dev.61.