Typings: MySQL option dateStrings has incorrect type

[tkalliom]

Environment

Knex version: master
Database + version: MySQL
OS: Linux

Issue is about TypeScript definitions, @lorefnon

Bug

The MySQL options have the field dateStrings?: boolean;. In addition to a boolean, the MySQL also supports giving a list of types which should be converted to strings. The corresponding definition in @types/mysql is dateStrings?: boolean | Array<'TIMESTAMP' | 'DATETIME' | 'DATE'>;. I was thinking perhaps the driver-specific part should actually be imported from @types/mysql, but maybe there is some reason it is not done that way?

[kibertoad]

Problem with importing external types is that if you make them a runtime dependency, they will be retained on runtime for everyone, and if you make them a devDependency, then TS builds for all users who haven't added them manually will start to fail too.
Would you be open to submitting a PR to fix the types?