Rely on less custom config, cut out travis ci, upgrade tools and dependencies

[jewell-lgtm]

Hi! I've been working on extending this library and thought I would push some of my changes upstream to this library.

The main changes:

• Use eslint over (deprecated) tslint
• add husky to lint staged files on commit
• switch to github actions rather than travis ci (one service fewer to replicate upstream)
• add automatic publish to npm action, simply tag a commit starting with v* e.g. v2.0.0 and a new version will be published to npm