Gitignore package-lock

[sarupbanskota]

Every time I run make bootstrap, there are several package-lock.json files created in the repo. I wasn't exactly sure if we wanna check them in, so instead of raising an issue asking what everybody thinks, I decided to make a PR anyway. Feel free to close it if it isn't necessary

[mention-bot]

@sarupbanskota, thanks for your PR! By analyzing the history of the files in this pull request, we identified @hzoo, @Kovensky and @loganfsmyth to be potential reviewers.

[xtuc]

Yes I agree, we should ignore it. I'm just wondering NPM5 is not covereded by our devEngines restrictions https://github.com/babel/babel/blob/7.0/package.json#L55.

[sarupbanskota]

@xtuc hmm fair enough, but considering we wanted to have Node 8 at least on Travis via #5807, I'm assuming we'll wanna also cover node 8 and npm 5? (happy to make the change)

[xtuc]

I don't find the issue anymore but I know we wanted to assert the developer's environment (Node version and NPM version) but that's not the case atm.

Would be nice if you have the time to bump our devEngines configuration. It should at least match our test infrastructure versions.

[hzoo]

We would want to keep it in source just like yarn.lock - the issue is that yarn doesn't handle npm 5 atm

[xtuc]

Yes but we maybe want a Yarn only workflow? Because otherwise we need to update both lock files.

[sarupbanskota]

exactly @xtuc, that is what I thought, that we wanna stick with just yarn. (not that I'm excited about it thanks to npm5 😉)

I'll bump the devEngines config tonight and update this PR

[sarupbanskota]

Bumped the engines (💭) to include node 8 and npm5.

💭 This was the first time I saw a devEngines option so I was googling it, but couldn't find much information on what package it's made available through. Reading npm/npm#9765 (comment), I thought it would be gbjs-scripts but that's not in our list. So maybe relevant code was copied, but then #5312 the original PR that introduced it doesn't have any extra code. Reading https://docs.npmjs.com/files/package.json#engines it seemed like engines does what we want so I stuck with just that, but couldn't find code that could be removed because of this change.

Lmk if you folks think I should make more changes!