Update dependencies and improve GitHub Actions CI configurations

[theoludwig]

What changes did you make? (Give an overview)

• Update dependencies to latest version
• Update CI files : add cache dependencies + update GitHub actions + add dependabot.yml and seperate Commit lint in another workflow than nodejs + Change the on event so it only runs on push/pull_request on master branch.
• Update .editorconfig to follow better standard editor config
• Fix TypeScript errors in tests files

Is there anything you'd like reviewers to focus on?

Currently we're running inside GitHub actions : linting, automated tests etc, on 3 version of Node.js [10.x, 12.x, 14.x] but we're also running 3 times Lint the Commit Messages but this doesn't depend on the node.js version so we could seperate in another workflow setting file so it runs only once. That's why I seperate Commit lint in another workflow than nodejs, see commitlint.yml. Also I changed the on event so it only runs once and not twice as it was the case when we push and it is a PR.

If everything is fine for you, we could release ts-standard@10.0.0 after this has been merged to master (up to you). Feel free to review my PR and tell me what changes you disagree etc. Oh also, we could add Branch protection rules, so we can't merge a PR to master if there are not at least 1 approved review.

[welcome[bot]]

🙌 Thanks for opening this pull request! You're awesome.

[theoludwig]

Hey @toddbluhm! 👋 Any news since then ? 😃

[welcome[bot]]

🎉 Congrats on getting your first pull request landed!