Remove ubuntu-16.04 from workflows (#1257)
Remove ubuntu-16.04 from workflows (#1257)

GitHub Actions no longer supports Ubuntu 16.04.
https://github.blog/changelog/2021-04-29-github-actions-ubuntu-16-04-lts-virtual-environment-will-be-removed-on-september-20-2021/
brianmario/mysql2,brianmario/mysql2,brianmario/mysql2