Add github actions to workflow.

[timronan]

Thank your for contributing to PH5

Before submitting a PR, please review the pull request guidelines: https://github.com/PIC-IRIS/PH5/blob/master/CONTRIBUTING.md#submitting-a-pull-request

What does this PR do?

This PR moves the CI/CD pipeline from Travis CI to Github Actions. All testing should remain consistent but the platform running the test will change.

Relevant Issues?

All PRs stuck because of lack of CI/CD pipeline.

Checklist

• [ ] This PR is not directly related to an existing issue (which has no PR yet).
• [ ] All tests pass.
• [ ] Any new or changed features have are documented.
• [ ] Changes have been added to CHANGELOG.txt .
• [ ] First time contributors have added your name to CONTRIBUTORS.txt .

[timronan]

Once we merge this branch, I am going to remove our webhook into Travis CI and it will no longer run PH5 test. The Github actions testing platform should actually start working on all new commits when this branch is merged. There shouldn't be any additional configurations.