chore: updating dev deps. check formatting on travis ci

[gndelia]

closes #210

I'll be doing some commits with --no-verify to force CI failure (to check it's working)

I also updated 4 dev dependencies

• lint-staged
• husky
• is-ci-cli (not required for the PR, but it's not a breaking change and given I was updating the CI conf...)
• prettier => in this case I did not go to the last up-to-date version, but to the latest stable without breaking changes - in this case 1.19.1. That's because in 1.19 they included support for parsing optional chaining (foo?.baz) which we use in TS files.
  I could update prettier to the latest but I thought it'd be better to do it in a separated PR as I think they changed some defaults and it may do the PR larger than it's required.

The breaking changes of these ☝️ is just dropping old node support, which is not required for linting our code

[gndelia]

This is ready to review
many changes in ts files are added because prettier was no run in a couple of them 🤔

[gndelia]

closing in favor of applying these changes in a PR targeting v4