Configure Github Actions to Build and Run Tests

[jurvis]

Purpose

Set up workflows for CI with Github Actions. Addresses #63.

This is dependent on #69 which brings most of our build toolchain to be runnable directly from the Xcode project.

Implementation

Create a build-frameworks workflow which first builds the files and then runs tests.

You can see an example of the results here: https://github.com/jurvis/libwally-swift/actions/runs/2252283407

Demo

Next Steps

Write a workflow on release tag that will build an xcframework and upload a ZIP to GitHub.

Additional Notes

I wasn't able to get the CI build with iOS Device working (see: https://github.com/jurvis/libwally-swift/runs/6244574594?check_suite_focus=true), but I was able to confirm on my computer that the framework builds okay for device as target.

I think there may be a separate issue with iPhoneSDK15.2, but not sure. Attaching gist of config.log error here: https://gist.github.com/jurvis/f45901634b5bab5b73db5ad6edf125cd (see line 984 to 1003). Will like some ideas if anyone has any.

[Sjors]

Nice! I'll review #69 first.

[jurvis]

Latest Github Action build with iOS Device + x86_64 host: https://github.com/jurvis/libwally-swift/actions/runs/2254436441

[Sjors]

95c91e7d0bfce894e49a2cb652d201752b8be872 looks good

[jurvis]

oops i closed this by accident

[Sjors]

It didn't let you reopen it?

[jurvis]

nope :( the "Reopen" button is greyed out for me