Update mocha to version 2.4.5 🚀

[greenkeeperio-bot]

Hello :wave:

:rocket::rocket::rocket:

mocha just published its new version 2.4.5, 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 mocha – otherwise use this branch to work on adaptions and fixes.

Happy fixing and merging :palm_tree:

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The new version differs by 85 commits (ahead by 85, behind by 1).

• 2a85944 Release v2.4.5
• 51c8ae4 update CHANGELOG.md for forthcoming v2.4.5 release
• e1bf728 reverts usage of chalk and all chalk-related changes thereafter; closes #2080
• 0d1bb21 add npm-debug.log to .gitignore
• 1fa6a79 Merge pull request #2082 from mislav/fix-assertions
• 29a679b Fix a number of assertions that weren't asserting anything
• cf513cb Release v2.4.4
• c3a1527 update changelog
• 4b37877 use browser field instead of --require; closes #2080
• 8de0ab6 Merge pull request #2076 from rstacruz/patch-2
• 608415d Release v2.4.3
• a4345ef stub chalk in browser, closes #2078
• b1b562e Add missing heading style
• 753a511 Release v2.4.2
• 8aafbb5 rebuild

There are 85 commits in total. See the full diff.

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