Merge pull request #767 from bacongobbler/repo-update

docs(upgrading-workflow): mention helm repo update

Author: Matthew Fisher

src/managing-workflow/upgrading-workflow.md

@@ -30,6 +30,7 @@ period of downtime while the database recovers from backup.
 First, find the name of the release helm gave to your deployment with `helm ls`, then run
 
 ```
+$ helm repo update
 $ helm upgrade <release-name> deis/workflow
 ```