Create GitHub actions linting and unit test automation using the existing .travis.yml as a template.

[lcarcaramo]

Since GitHub actions is built into GitHub, it probably makes sense to use GitHub Actions instead of Travis for pyRACF listing and unit test automation.

• GitHub Actions documentation: https://docs.github.com/en/actions

[ElijahSwiftIBM]

Pull Request #7 has been opened to address this concern.

[lcarcaramo]

PR merged.