Update chai to the latest version 🚀

[greenkeeper]

Version 4.1.0 of chai just got published.

Dependency	chai
Current Version	4.0.2
Type	devDependency

The version 4.1.0 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 chai.
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.

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Release Notes

4.1.0 / 2017-07-11

This release includes one new feature and a few bug fixes.

New Features

• Add ES6 collection support to include() (#970, #994; @shvaikalesh)

Bug Fixes

• Allow dates for isBelow and isAbove assertions (#980, #990; @v1adko)
• fix: check target's type in .property assertion (#992; @meeber)

Chores

• Add a missing var keyword found by lgtm.com (#988; @samlanning)
• refactor: expectTypes to access ssfi flag (#993; @meeber)
• Create CODEOWNERS (#1004; @keithamus)

Commits

The new version differs by 16 commits.

• df9073c Merge pull request #998 from v1adko/make-release
• cad9933 Merge pull request #1004 from chaijs/code-owners
• cf70b11 Create CODEOWNERS
• 3397dda Merge pull request #1005 from meeber/skip-failing-tests
• 11a6f85 test: skip failing .include tests in IE11
• 45cb327 chai@4.1.0
• 2eddd79 Add ES6 collection support to include() (#994)
• 3c932e2 feat: allow dates for isBelow and isAbove assertions (#990)
• 3bcb21c Merge pull request #979 from chaijs/greenkeeper/browserify-14.4.0
• 5daceab Merge pull request #988 from samlanning/missing-var
• 9116bc8 Merge pull request #993 from meeber/refactor-expect-types
• 351e968 Merge pull request #992 from meeber/property-target-type
• e7b2384 refactor: expectTypes to access ssfi flag
• e6ddf64 fix: check target's type in .property assertion
• 7e466af Add a missing var keyword found by lgtm.com

There are 16 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.

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