Fix PHPCS issues

Author: schlessera

src/Cache_Command.php

@@ -439,7 +439,7 @@ public function flush_group( $args, $assoc_args ) {
 	 */
 	public function pluck( $args, $assoc_args ) {
 		list( $key ) = $args;
-		$group     = Utils\get_flag_value( $assoc_args, 'group' );
+		$group       = Utils\get_flag_value( $assoc_args, 'group' );
 
 		$value = wp_cache_get( $key, $group );