down: Reject all arguments

The down command silently ignored all arguments, which might cause
confusion and/or outages if someone expects `docker-compose down
$service` to be the opposite of `docker-compose up $service`, rather
than turning down everything.

Signed-off-by: Jille Timmermans <jille@quis.cx>

cmd/compose/down.go

@@ -59,6 +59,7 @@ func downCommand(p *projectOptions, backend api.Service) *cobra.Command {
 		RunE: Adapt(func(ctx context.Context, args []string) error {
 			return runDown(ctx, backend, opts)
 		}),
+		Args:              cobra.NoArgs,
 		ValidArgsFunction: noCompletion(),
 	}
 	flags := downCmd.Flags()