Update README with Jenkins badge change (see docker-library/docs#697)

Author: tianon

README.md

@@ -10,5 +10,7 @@ See a change merged here that doesn't show up on the Docker Hub yet? Check [the
 
 -	[Travis CI:  
 	![build status badge](https://img.shields.io/travis/docker-library/elasticsearch/master.svg)](https://travis-ci.org/docker-library/elasticsearch/branches)
+-	[Automated `update.sh`:  
+	![build status badge](https://doi-janky.infosiftr.net/job/update.sh/job/elasticsearch/badge/icon)](https://doi-janky.infosiftr.net/job/update.sh/job/elasticsearch)
 
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