Use GitHub actions for CI

[serbinsh]

General reference
https://docs.github.com/en/actions/quickstart

References for use with R code

https://usethis.r-lib.org/reference/github_actions.html
usethis::use_gh_actions_ci()

https://github.com/r-lib/actions

[serbinsh]

Another more detailed example
https://github.com/FoRTExperiment/fortedata/tree/master/.github/workflows

[serbinsh]

Here are perhaps more easy to work with examples here: https://github.com/TESTgroup-BNL/spectratrait/tree/master/.github/workflows

These are running with our spectratrait package. I could see starting simple to make sure the package complies but then adding in some test runs to ensure everything is working. We can add build status to the README. e.g. see the bottom of the README on spectratrait