update version in README

Change-Id: I407c5800b7452681875d53ff5ddd0f831f50c25c
diff --git a/README.rst b/README.rst
index ab38671..0821b40 100644
--- a/README.rst
+++ b/README.rst
@@ -24,7 +24,7 @@
       kubernetes:
         common:
           hyperkube:
-            image: gcr.io/google_containers/hyperkube:v1.4.6
+            image: gcr.io/google_containers/hyperkube:v1.5.2
         pool:
           network:
             calicoctl: