test: faster builds maybe

[janl]

[janl]

this re-adds package-lock.json again which reduces nom install time on travis from ~22s to ~10s. Which is a ~5% impact on total runtime.

We should discuss whether we want to add this.

If we do, I’d recommend we all install the npm-merge-driver, that helps with auto-resolving lock file conflicts.

[janl]

@espy @hulkoba @Realtin review pls <3

[rmehner]

Random Drive By (I'm working on all my emails right now and this just popped up): If you use a current npm version and you do have a package-lock.json, then you might wanna use npm ci instead of npm install, which will speed up the install even more.

[janl]

@rmehner thanks, yes! :)

This is a one-step-at-a-time thing where I want to bring back package-lock.json :)