Merge pull request #889 from ssurenr/190-release

Update release version for v1.9.0

Author: ssurenr

docs/RELEASE-NOTES.rst

@@ -1,7 +1,7 @@
 Release Notes for BIG-IP Controller for Kubernetes
 ==================================================
 
-next-release
+v1.9.0
 ------------
 
 Added Functionality