Choosing Windows CI

[methane]

#934 may introduce platform dependent code.
I want to add Windows CI for it.

• Travis-CI has only beta support for Windows. And it doesn't preinstall MySQL.
• AppVeyor
• Azure Pipelines

Which do you like?

[ikesyo]

GitHub Actions can be used now:

• https://docs.github.com/en/actions/reference/virtual-environments-for-github-hosted-runners#supported-runners-and-hardware-resources
• https://github.com/actions/virtual-environments/blob/main/images/win/Windows2019-Readme.md#tools

[shogo82148]

Windows CI has been moved into GitHub Actions. #1190 #1183