CHANGELOG.md in google-cloud-datastore-1.5.1 vs CHANGELOG.md in google-cloud-datastore-1.5.2

@@ -1,6 +1,12 @@
 # Release History
 
+### 1.5.2 / 2019-04-29
+
+* Add AUTHENTICATION.md guide.
+* Update generated documentation.
+* Extract gRPC header values from request.
+
 ### 1.5.1 / 2019-02-13
 
 * Add `ReadOnlyTransaction` convenience methods:
   * Add `ReadOnlyTransaction#query`
   * Add `ReadOnlyTransaction#gql`