CI: move from Travis-CI to GitHub Actions

[victorperin]

TravisCI is delaying a lot of build jobs recently, github actions could help fix this.

Important notes about the CI:

• [x] We need to check tests on every major platform:
  • [x] Linux
  • [x] Windows
  • [x] MacOS
• [x] We also need to run (in all the platforms) against all active NodeJS versions.
  • [x] v15
  • [x] v14
  • [x] v12
  • [x] v10

The most important workflow, right now is:

• [x] preparation
  • [x] npm ci
  • [x] npm run build
• [x] tests
  • [x] npm run linter
  • [x] npm run test:coverage
• [x] after
  • [x] coverage report
• [x] deploy (runs only 1 time, after all tests in all those environments)
  • [x] npm run semantic-release