Update jenkins image

Change-Id: Ia4b75c829ca2d142215900b563ab9a532ebfd1a7
diff --git a/docker/swarm/service/jenkins.yml b/docker/swarm/service/jenkins.yml
index 3069dc6..16dee71 100644
--- a/docker/swarm/service/jenkins.yml
+++ b/docker/swarm/service/jenkins.yml
@@ -1,6 +1,6 @@
 parameters:
   _param:
-    docker_image_jenkins: tcpcloud/jenkins:2.50
+    docker_image_jenkins: tcpcloud/jenkins:2.52
   docker:
     client:
       service: