MySQL DDL parser - issue with COLLATE in functions

After fixing the issue DBZ-1331 my debezium process stopped on parsing function definition. It looks the Antlr grammar was not able to parse function that returns string with custom collation, like:

CREATE FUNCTION `func1`() RETURNS varchar(5) CHARSET utf8 COLLATE utf8_unicode_ci BEGIN 
  return '12345'; 
END;

But function like this is proper MySQL function (I tested it on MariaDB, but according to the docs it should work as well in MySQL):

MariaDB [superset]> delimiter //
MariaDB [superset]> CREATE FUNCTION `func1`() RETURNS varchar(5) CHARSET utf8 COLLATE utf8_unicode_ci begin return '12345'; end;
    -> //
Query OK, 0 rows affected (0.03 sec)

MariaDB [superset]> delimiter ;
MariaDB [superset]> select func1()
    -> ;
+---------+
| func1() |
+---------+
| 12345   |
+---------+
1 row in set (0.00 sec)

I'm going to attach the pull request in a few minutes