Test GitHub Actions

[jasonratcliff]

Add workflow .yaml configuration to implement continuous integration via GitHub Actions (#46).

Cache

• Caching dependencies to speed up workflows
  • https://github.com/actions/cache

Note the default behavior prevents saving the action cache unless job completes to success:

https://www.github.com/actions/cache/issues/92

[jasonratcliff]

Job hangs for unsupported runner; omit patch name to designate a supported runner:

• https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources