Admin Reskin: Add more margin below the plugin card header

Author: t-hamano

src/wp-admin/css/list-tables.css

@@ -1608,7 +1608,7 @@ div.action-links,
 }
 
 .plugin-card h3 {
-	margin: 0 12px 12px 0;
+	margin: 0 12px 16px 0;
 	font-size: 18px;
 	line-height: 1.3;
 }