Check if using a child theme before comparing version of GPP themes

updater.diff

@@ -523,8 +524,13 @@
 		private function get_local_version() {
 			if ( $this->is_theme() ) {
 				$theme_data = wp_get_theme();
-
-				return $theme_data->Version;
+					if( $theme_data->parent() ){
+						$parent_theme_data =  wp_get_theme( $theme_data->Template );
+						return $parent_theme_data->Version;
+					}
+					else{
+						return $theme_data->Version;
+					}
 			} else {
 				$plugin_data = get_plugin_data( $this->plugin_file, false );