Fix issue where updated containers aren't stopped

Used 'break' instead of 'continue' resulting in the termination of the
stop container loop any time the watchtower container is encountered.

actions/update.go

@@ -41,7 +41,7 @@ func Update(client container.Client) error {
 		container := containers[i]
 
 		if container.IsWatchtower() {
-			break
+			continue
 		}
 
 		if container.Stale {