Clarify role removal instructions in release notes (#308)

The release notes were adjusted to make the instructions about role
removal more explicit. The role's access control entries should be
removed and the role itself as well, as detailed in the updated
documentation.

ReleaseNotes.md

@@ -48,7 +48,8 @@ Accounts created by the ACS installation will have been updated to be
 members of the Group, but ACLs referencing the Client Role and the Role
 itself will not have been removed. Any local accounts using the Role
 should be updated to be members of the Group instead, and then any
-access control entries referencing the Role should be removed.
+access control entries referencing the Role (and the role itself)
+should be removed.
 
 ### TLS certificate namespace
 IngressRoutes are now namespaced to the namespace of the chart release.