Add comment about service account annotations

Signed-off-by: Naseem <naseemkullah@gmail.com>

pkg/chartutil/create.go

@@ -103,6 +103,7 @@ fullnameOverride: ""
 serviceAccount:
   # Specifies whether a service account should be created
   create: true
+  # Annotations to add to the service account
   annotations: {}
   # The name of the service account to use.
   # If not set and create is true, a name is generated using the fullname template