Adding dep update command to att-workflow instructions

Change-Id: I5ce6d7b22f93f2ead5e2581b7501ff3dbe617994
diff --git a/profiles/rcord/workflows/att.md b/profiles/rcord/workflows/att.md
index 1ec4084..fa4a3e6 100644
--- a/profiles/rcord/workflows/att.md
+++ b/profiles/rcord/workflows/att.md
@@ -17,6 +17,7 @@
 ### Install the `att-workflow` chart
 
 ```shell
+helm dep update xos-profiles/att-workflow
 helm install -n att-workflow xos-profiles/att-workflow
 ```