Update eslint to version 2.4.0 🚀

[greenkeeperio-bot]

Hello 👋

🚀🚀🚀

eslint just published its new version 2.4.0, which is not covered by your current version range.

If this pull request passes your tests you can publish your software with the latest version of eslint – otherwise use this branch to work on adaptions and fixes.

Happy fixing and merging 🌴

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GitHub Release

• 97b2466 Fix: estraverse/escope to work with unknowns (fixes #5476) (Nicholas C. Zakas)
• 641b3f7 Fix: validate the type of severity level (fixes #5499) (Shinnosuke Watanabe)
• 9ee8869 Docs: no-unused-expressions - add more edge unusable and usable examples (Brett Zamir)
• 56bf864 Docs: Create parity between no-sequences examples (Brett Zamir)
• 13ef1c7 New: add --parser-options to CLI (fixes #5495) (Jordan Harband)
• ae1ee54 Docs: fix func-style arrow exception option (Craig Martin)
• 91852fd Docs: no-lone-blocks - show non-problematic (and problematic) label (Brett Zamir)
• b34458f Docs: Rearrange rules for better categories (and improve rule summaries) (Brett Zamir)
• 1198b26 Docs: Minor README clarifications (Brett Zamir)
• 03e6869 Fix: newline-before-return: bug with comment (fixes #5480) (mustafa)
• ad100fd Fix: overindent in VariableDeclarator parens or brackets (fixes #5492) (David Greenspan)
• 9b8e04b Docs: Replace all node references to Node.js which is the official name (Brett Zamir)
• cc1f2f0 Docs: Minor fixes in no-new-func (Brett Zamir)
• 6ab81d4 Docs: Distinguish examples in rules under Best Practices part 1 (Mark Pedrotti)
• 9c6c70c Update: add allowParens option to no-confusing-arrow (fixes #5332) (Burak Yigit Kaya)
• 979c096 Docs: Document linebreak-style as fixable. (Afnan Fahim)
• 9f18a81 Fix: Ignore destructuring assignment in object-shorthand (fixes #5488) (alberto)
• 5d9a798 Docs: README.md, prefer-const; change modified to reassigned (Michiel de Bruijne)
• 38eb7f1 Fix: key-spacing checks ObjectExpression is multiline (fixes #5479) (Kevin Partington)
• 9592c45 Fix: no-unmodified-loop-condition false positive (fixes #5445) (Toru Nagashima)

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