meta(mariadb): add mariadb to CI

Please make sure to review and check all of these items:

[ ] Does npm run test pass with this change (including linting)?
[ ] Does the description below contain a link to an existing issue (Closes #[issue]) or a description of the issue you are solving?
[ ] Have you added new tests to prevent regressions?
[ ] Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?

sequelize / cli