Chore: upgrade deps.

[aladdin-add]

What is the purpose of this pull request? (put an "X" next to item)

[x] Other, please explain:

What changes did you make? (Give an overview)
upgrade deps to latest version.

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

[eslintbot]

LGTM

[mention-bot]

@aladdin-add, thanks for your PR! By analyzing the history of the files in this pull request, we identified @alberto, @nzakas and @mysticatea to be potential reviewers.

[ilyavolodin]

As mentioned in Greenkeeper issue, we have to have a good reason to update dependancies. We don't update them whenever the new version comes out. I'm not sure we need to update them right now, unless you know of a good reason to do so.

[not-an-aardvark]

@ilyavolodin What's the disadvantage of upgrading dependencies?

By the way, this was also discussed in #8304.

[platinumazure]

At least for packages we maintain ourselves (espree), I think it makes some sense to offer latest and greatest if we can. Otherwise, I can see both sides.

[aladdin-add]

As mentioned in Greenkeeper issue, we have to have a good reason to update dependancies. We don't update them whenever the new version comes out.

agree to this. but what is “a good reason”. since we have a very good test coverage, (maybe) it is safe to upgrade to latest.

[gyandeeps]

I support periodic updates like these. I think there is no harm doing this periodically.

[corbinu]

I would also prefer that the dependencies are updated regularly, but just my two cents

[not-an-aardvark]

@ilyavolodin It looks like three team members are in favor of this PR. Are you okay with it being merged?

[ilyavolodin]

I'm fine with merging this one. Updating deps once in a while is perfectly fine. I just don't really want to update as soon as a new version of dependency comes out.