Update jenkins version in README

Author: emmetog

README.md

@@ -38,7 +38,7 @@ Role Variables
 --------------
 
 ```yml
-jenkins_version: "1.642.4" # The exact version of jenkins to deploy
+jenkins_version: "2.19.2" # The exact version of jenkins to deploy
 jenkins_url: "http://127.0.0.1" # The url that Jenkins will be accessible on
 jenkins_port: "8080" # The port that Jenkins will listen on
 jenkins_home: /data/jenkins # The directory on the server where the Jenkins configs will live
@@ -284,4 +284,4 @@ I am the founder of [NimbleCI](https://nimbleci.com) which
 builds Docker containers for feature branch workflow projects in Github.
 
 I blog on my [personal blog](http://blog.emmetogrady.com) and 
-about Docker related things on the [NimbleCI blog](https://blog.nimbleci.com).
+about Docker related things on the [NimbleCI blog](https://blog.nimbleci.com).