Ci tests (#2)

[emilpriver]

hey 👏

Added Ci to build the project on:

• Ubuntu 22.04
• Ubuntu 20.04
• macos 12
• macos 11
• Windows 2022 (server)
• Windows 2019 (server)

Don't seem as we are able to use for example windows 10 but windows server does the job aswell.

I also added a linter which complains about normal problems: https://github.com/rust-lang/rust-clippy and rust fmt check.

[emilpriver]

It's is possible to build/test into different rust targets. But don't think it needed atm

[emilpriver]

Did see that GH is not running the actions unless you merge it @benja but here is a example of all tests: https://github.com/emilpriver/cloup/actions/runs/3269186840

[emilpriver]

I recommend to Squash this PR