vendor: update buildkit to master@9624ab4

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

vendor/github.com/docker/cli/cli-plugins/manager/manager.go

@@ -224,3 +224,8 @@ func PluginRunCommand(dockerCli command.Cli, name string, rootcmd *cobra.Command
 	}
 	return nil, errPluginNotFound(name)
 }
+
+// IsPluginCommand checks if the given cmd is a plugin-stub.
+func IsPluginCommand(cmd *cobra.Command) bool {
+	return cmd.Annotations[CommandAnnotationPlugin] == "true"
+}