Update sessions.sql

Author: dereuromark

config/schema/sessions.sql

@@ -12,4 +12,4 @@ CREATE TABLE `sessions` (
   `data` blob DEFAULT NULL, -- for PostgreSQL use bytea instead of blob
   `expires` int(10) unsigned DEFAULT NULL,
   PRIMARY KEY (`id`)
-) ENGINE=InnoDB DEFAULT CHARSET=utf8;
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;