Update mock-fs to version 4.0.0 🚀

[greenkeeperio-bot]

Hello lovely humans,

mock-fs just published its new version 4.0.0.

State	Update 🚀
Dependency	mock-fs
New version	4.0.0
Type	devDependency

This version is not covered by your current version range.

Without accepting this pull request your project will work just like it did before. There might be a bunch of new features, fixes and perf improvements that the maintainers worked on for you though.

I recommend you look into these changes and try to get onto the latest version of mock-fs.
Given that you have a decent test suite, a passing build is a strong indicator that you can take advantage of these changes by merging the proposed change into your project. Otherwise this branch is a great starting point for you to work on the update.

Do you have any ideas how I could improve these pull requests? Did I report anything you think isn’t right?
Are you unsure about how things are supposed to work?

There is a collection of frequently asked questions and while I’m just a bot, there is a group of people who are happy to teach me new things. Let them know.

Good luck with your project ✨

You rock!

🌴

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The new version differs by 54 commits .

• 84523af 4.0.0
• 01e3db2 Upgrade notes
• 10f98fc Merge pull request #194 from ciaranj/expose_root_of_mock_filesystem
• 6a06eda Exposes the root mocked filesytem if the mock is currently applied.
• b3d19b3 4.0.0-beta.1
• e874477 Merge pull request #193 from tschaub/four
• 4e7d0e3 Document breaking changes
• 56db880 Update to eslint@3.11.1
• 5c74f6f Merge pull request #182 from tschaub/binding
• 4426ebc Only override process.binding('fs')
• 479d815 Pending tests
• 143f7ff Updated linter and config
• 4142982 Test on Node 4 and above
• 6645104 3.12.1
• 992b48f Log changes

There are 54 commits in total. See the full diff.

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