Improve global style enqueuer - file modification timestamp (#150)

This was a browser is forced to load the new file if you make modifications to your custom blocks CSS file.

Very important specially if you use a CDN.

Co-authored-by: fvmartin <[email protected]>

php/Blocks/Loader.php

@@ -457,7 +457,7 @@ protected function enqueue_global_styles() {
 				'genesis-custom-blocks__global-styles',
 				$stylesheet_url,
 				[],
-				wp_get_theme()->get( 'Version' )
+				filemtime( $stylesheet_path )
 			);
 		}
 	}