Add github release to release process (#65)

dev/README_RELEASE_CLIENT.md

diff --git a/dev/README_RELEASE_CLIENT.md b/dev/README_RELEASE_CLIENT.md
index 902b966..07fd129 100644
--- a/dev/README_RELEASE_CLIENT.md
+++ b/dev/README_RELEASE_CLIENT.md
@@ -397,6 +397,10 @@
     git push origin ${VERSION}
     ```
 
+## Create release on GitHub
+
+Create a new release on GitHub with the release notes and assets from the release svn.
+
 ## Notify developers of release
 
 See Airflow process documented [here](https://github.com/apache/airflow/blob/master/dev/README_RELEASE_AIRFLOW.md#notify-developers-of-release) (just replace Airflow with Airflow Client)