Typescript wrong named longlong in place of bigint

partially described https://github.com/mariadb-corporation/mariadb-connector-nodejs/pull/284

problem is there is javascript describe `BIGINT` (https://github.com/mariadb-corporation/mariadb-connector-nodejs/blob/master/lib/const/field-type.js#L17) while typescript use `longlong` https://github.com/mariadb-corporation/mariadb-connector-nodejs/blob/master/types/index.d.ts#L931 and https://github.com/mariadb-corporation/mariadb-connector-nodejs/blob/master/types/index.d.ts#L998

goal of this task is to unify BIGINT use