[Gallery] Bump version to 2.3 (#321)



Former-commit-id: 7e268979ebe587fb0b95f202be726c8fcc6fc848
diff --git a/pubspec.yaml b/pubspec.yaml
index dab84eb..69f1d03 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,7 +1,7 @@
 name: gallery
 description: A resource to help developers evaluate and use Flutter.
 
-version: 2.2.0+020200
+version: 2.3.0+020300
 
 environment:
   sdk: ">=2.3.0 <3.0.0"