Spago config and Github Actions

[peterbecich]

This PR provides Spago support and Github Actions.

Build and tests appear to succeed: https://github.com/peterbecich/purescript-foreign-generic/runs/2045557932?check_suite_focus=true

I'm unclear on which libraries are sticking with Bower; please close if purescript-foreign-generic is one of them. Thanks

[peterbecich]

@srghma ,

It is feasible to create a new repository in https://github.com/purescript/ or https://github.com/purescript-contrib, instead of this new organization https://github.com/purescript-open-community?

[jamesdbrock]

@jamesdbrock can move https://github.com/purescript-open-community/purescript-open-foreign-generic to https://github.com/purescript-contrib ?

Or we could move this package to https://github.com/rowtype-yoga ? That might be a better place for it.

But also, I think there is a good reason why this package is abandoned. I think there are better alternatives these days:

1. Argonaut
2. Simple.JSON
3. F Monad
4. codec-argonaut

See https://github.com/xc-jp/blog-posts/blob/master/_posts/2021-10-07-PureScript-React.md#foreign