Update fs-extra to the latest version 🚀

[greenkeeper]

Version 4.0.0 of fs-extra just got published.

Dependency	fs-extra
Current Version	3.0.1
Type	devDependency

The version 4.0.0 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 fs-extra.
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.

---

Commits

The new version differs by 20 commits.

• 3d25473 4.0.0
• eb16cda Fix docs lint error
• bd0a200 Merge pull request #449 from jprichardson/read-write-obj
• 9b624d2 Upgrade standard-markdown devDep
• df6aa07 Merge pull request #458 from jprichardson/prevent-move-into-itself
• f015563 Merge pull request #459 from jprichardson/rimraf
• ea2e2a4 Merge pull request #460 from jprichardson/docs
• 395f6b0 Document writeJson() & outputJson() options
• 33fbe78 Apply upstream rimraf fixes
• d99d8a1 Fix isSrcSubdir() split bug
• f8f441a Refactor isSrcSubdir() in move
• 16dc81e Fix the issue of moving into itself
• 85f531e Merge pull request #450 from jprichardson/windows-tests
• 5f888ba Skip copy & copySync timestamp tests on 32-bit computers
• 5a8d568 Add docs for using promises with fs.read() & fs.write()

There are 20 commits in total.

See the full diff

Not sure how things should work exactly?

There is a collection of frequently asked questions and of course you may always ask my humans.

---

Your Greenkeeper Bot 🌴

[coveralls]

Coverage remained the same at 100.0% when pulling 785021b on greenkeeper/fs-extra-4.0.0 into 248e069 on master.