Add windows support

[piksel]

With this change it seems like windows is fully supported.

Usually, building for all platforms on go works out of the box, but since this uses cgo, I think you need to build the windows binaries on windows (or using an appropriate xplat toolchain setup).

[mavogel]

awesome @piksel! Can you also add tests in GH actions for windows? You might find the windows related commands from here useful: https://github.com/gesellix/awsu/commits/master

[piksel]

I'm not sure I understand what you mean. The gesellix@ed157b1 commit only deals with a symlink (which does work on recent versions of windows).
The test CI action probably does not work on windows, but that is because it relies on tools that might not be available in the windows image:

• make
• xargs
• grep

Why isn't this used for tests?

go test ./... -cover

(the test PHONY in Makefile is this:)

go list ./... | grep -v exp | xargs go test -cover

[mavogel]

I'm sorry, I wasn't precise enough. I was more referring to this commit: gesellix@663bc0b
Feel free to adapt the makefile accordingly :) The repo was outdated and we are refurbishing it now.

[piksel]

I added windows as a matrix target to the test workflow. Gesellix' fork also included macos, and built on ubuntu-latest instead of ubuntu-20.04, but I figured this was what was inside the scope of this PR.
Adding support to goreleaser as well might be tricky, since the dependencies work very differently on windows and linux. Have not tried it though...

[mavogel]

Awesome :) thanks. Regarding the builds: we will address this in #56