Use the shared travis config with auto-updates for node releases

[dominykas]

tl;dr: I'd like to open a PR to replace the node_js section in the .travis.yml with an imported https://github.com/nodejs/ci-config-travis/blob/master/lts/gte-8.yml

Background: Package Maintenance WG has built a repository of shared Travis CI imports. The imports will be automatically updated as new Node.js versions get released.

Judging by what's inside the current .travis.yml here, and the missing engines in the package.json, I suspect that the lts upgrade policy is the right fit (it adds new versions as soon as they are released, never removes LTS versions, removes non-LTS versions when they reach EOL).

Is that OK?

[richardlau]

I have no objections. I'd also be open to moving from Travis over to GitHub Actions like we have done for several other repositories in the nodejs org.

[dominykas]

Opened #86 - as for GH actions - keep an eye out for https://github.com/nodejs/ci-config-github-actions (once we get that figured out...)