Update mocha requirement from 5.2.0 to 6.0.2

Updates the requirements on mocha to permit the latest version.

Release notes

Sourced from mocha's releases.

v6.0.2

6.0.2 / 2019-02-25

🐛 Fixes

Two more regressions fixed:

• #3768: Test file paths no longer dropped from mocha.opts ([@​boneskull](https://github.com/boneskull))
• #3767: --require does not break on module names that look like certain node flags ([@​boneskull](https://github.com/boneskull))

Changelog

Sourced from mocha's changelog.

6.0.2 / 2019-02-25

🐛 Fixes

Two more regressions fixed:

• #3768: Test file paths no longer dropped from mocha.opts ([@​boneskull](https://github.com/boneskull))
• #3767: --require does not break on module names that look like certain node flags ([@​boneskull](https://github.com/boneskull))

6.0.1 / 2019-02-21

The obligatory round of post-major-release bugfixes.

🐛 Fixes

These issues were regressions.

• #3754: Mocha again finds test.js when run without arguments ([@​plroebuck](https://github.com/plroebuck))
• #3756: Mocha again supports third-party interfaces via --ui ([@​boneskull](https://github.com/boneskull))
• #3755: Fix broken --watch ([@​boneskull](https://github.com/boneskull))
• #3759: Fix unwelcome deprecation notice when Mocha run against languages (CoffeeScript) with implicit return statements; returning a non-undefined value from a describe callback is no longer considered deprecated ([@​boneskull](https://github.com/boneskull))

📖 Documentation

• #3738: Upgrade to @mocha/docdash@2 ([@​tendonstrength](https://github.com/tendonstrength))
• #3751: Use preferred names for example config files ([@​Szauka](https://github.com/Szauka))

6.0.0 / 2019-02-18

🎉 Enhancements

• #3726: Add ability to unload files from require cache ([@​plroebuck](https://github.com/plroebuck))

🐛 Fixes

• #3737: Fix falsy values from options globals ([@​plroebuck](https://github.com/plroebuck))
• #3707: Fix encapsulation issues for Suite#_onlyTests and Suite#_onlySuites ([@​vkarpov15](https://github.com/vkarpov15))
• #3711: Fix diagnostic messages dealing with plurality and markup of output ([@​plroebuck](https://github.com/plroebuck))
• #3723: Fix "reporter-option" to allow comma-separated options ([@​boneskull](https://github.com/boneskull))
• #3722: Fix code quality and performance of lookupFiles and files ([@​plroebuck](https://github.com/plroebuck))
• #3650, #3654: Fix noisy error message when no files found ([@​craigtaub](https://github.com/craigtaub))
• #3632: Tests having an empty title are no longer confused with the "root" suite ([@​juergba](https://github.com/juergba))
• #3666: Fix missing error codes ([@​vkarpov15](https://github.com/vkarpov15))
• #3684: Fix exiting problem in Node.js v11.7.0+ ([@​addaleax](https://github.com/addaleax))
• #3691: Fix --delay (and other boolean options) not working in all cases ([@​boneskull](https://github.com/boneskull))
• #3692: Fix invalid command-line argument usage not causing actual errors ([@​boneskull](https://github.com/boneskull))
• #3698, #3699: Fix debug-related Node.js options not working in all cases ([@​boneskull](https://github.com/boneskull))
• #3700: Growl notifications now show the correct number of tests run ([@​outsideris](https://github.com/outsideris))
• #3686: Avoid potential ReDoS when diffing large objects ([@​cyjake](https://github.com/cyjake))
• #3715: Fix incorrect order of emitted events when used programmatically ([@​boneskull](https://github.com/boneskull))

... (truncated)

Commits

• 00a895f Release v6.0.2
• 1edce76 update CHANGELOG for v6.0.2 [ci skip]
• 347e9db fix broken positional arguments in config; ensure positional args are unique;...
• 9e31e9d fix handling of bareword args matching node flags; closes #3761
• 6535965 Update "karma-browserify" to eliminate Karma middleware warning (#3762)
• 37febb6 improve issue template. (#3411)
• 6d3d6b4 Release v6.0.1
• 2146ece update CHANGELOG.md for v6.0.1
• 7c9221d backout deprecation of value returned from suite; closes #3744
• b7cfceb fix --watch not finding any files to execute; closes #3748
• Additional commits viewable in compare view

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