allow to supply custom isSqlQuery helper or use better library

Toying with the plugin, I'm coming across valid SQL queries that aren't recognized, such as:

SELECT * FROM article a WHERE NOT a.archived

-- or

SELECT * FROM article a WHERE (a.authz & 8)::bool

One solution would be to either allow users to supply their own SQL parser (though I haven't checked if eslint allows to pass functions as settings values in .eslintrc.js), or replace the sql-parse, which seems unmaintained, with something else.