ci: switch travis ci for github actions

[erisu]

• Drop Travis CI
• Add GitHub Actions
• Add package-lock.json to use npm cit
• Add nyc code coverage dependency
• Send coverage report to codecov service
• Update README CI badge to GitHub Actions

Overall goal, unify services used across repo. Travis CI is a slow service during peak hours and its something that is unbearable. This is caused by the resources of the service is shared across all Apache projects. If people have limited time to review and/or do releases, waiting for tests should not be a bottleneck.

[NiklasMerz]

I generally agree that Github actions is more convenient than Travis which can be slow and time out.

Code looks good to me,too. Do we want to add package-lock.json to Git with this PR? Is this intentional? I still don't know if adding package-lock is a good idea for librariees like this one.

[erisu]

• Commit package-lock.json PR: Commit package-lock.json cordova#4

Per NPMJS:

It is highly recommended you commit the generated package lock to source control

Anyone using this library should install it though npm install xcode which does not use the package-lock.json as it is never bundled with the package.

[NiklasMerz]

* Commit `package-lock.json` PR: [apache/cordova#4](https://github.com/apache/cordova/issues/4)

Per NPMJS:

It is highly recommended you commit the generated package lock to source control

Anyone using this library should install it though npm install xcode which does not use the package-lock.json as it is never bundled with the package.

Thank you. I learned something new!

[NiklasMerz]

LGTM 👍

[timbru31]

LGTM, too

[timbru31]

@NiklasMerz - FYI: apache/cordova#4