add an entry in the changelog

diff --git a/CHANGELOG.md b/CHANGELOG.md
index cb264be..1e9e0a4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.2.1-dev
+
+* Update the value of the pubspec `repository` field.
+
 ## 1.2.0
 
 * Fix `Characters.where` which unnecessarily did the iteration and test twice.

diff --git a/pubspec.yaml b/pubspec.yaml
index 88a87f7..977e4a7 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml

@@ -1,5 +1,5 @@
 name: characters
-version: 1.2.0
+version: 1.2.1-dev
 description: String replacement with operations that are Unicode/grapheme cluster aware.
 repository: https://github.com/dart-lang/characters