Support parsing data-modifying statements in WITH

[tsmacdonald]

This is legal in Postgres

But fails

(deftest complicated-mutations-test
  (is (= #{"delete" "insert"}
         (mutations "WITH outdated_orders AS (
                       DELETE FROM orders
                       WHERE
                         date <= '2018-01-01'
                       RETURNING *
                     )
                     INSERT INTO order_log
                     SELECT * from outdated_orders;"))))

with

macaw.core-test
1 non-passing tests:

Error in complicated-mutations-test

expected: (=
	   #{"delete" "insert"}
	   (mutations
	    "WITH outdated_orders AS (
                       DELETE FROM orders
                       WHERE
                         date <= '2018-01-01'
                       RETURNING *
                     )
                     INSERT INTO order_log
                     SELECT * from outdated_orders;"))

   error: net.sf.jsqlparser.JSQLParserException: net.sf.jsqlparser.parser.ParseException: Encountered unexpected token: "DELETE" "DELETE"
    at line 2, column 24.

Was expecting:

    "WITH"