CI/CD: move from Travis to Github Actions

[anuveyatsu]

Since Travis-ci.org is now not working, we want to use this opportunity to move to GH Actions that is default in our projects.

Acceptance criteria

• [x] The tests are running in the CI using GH Actions

Tasks

• [x] Remove Travis config
• [x] Add GH Actions config (using node v12)
• [x] Run tests in the CI

[anuveyatsu]

FIXED in #198