chore(deps): update dependency mocha to v5.0.3

[renovate[bot]]

This Pull Request updates dependency mocha from v5.0.2 to v5.0.3

Release Notes

### [`v5.0.3`](https://github.com/mochajs/mocha/blob/master/CHANGELOG.md#​503--2018-03-06) This patch features a fix to address a potential "low severity" [ReDoS vulnerability](https://snyk.io/vuln/npm:diff:20180305) in the [diff](https://npm.im/diff) package (a dependency of Mocha). #### :lock: Security Fixes - [#​3266]: Bump `diff` to v3.5.0 ([@​anishkny]) #### :nut_and_bolt: Other - [#​3011]: Expose `generateDiff()` in `Base` reporter ([@​harrysarson]) [#​3266]: `https://github.com/mochajs/mocha/pull/3266` [#​3011]: `https://github.com/mochajs/mocha/issues/3011` [@​anishkny]: https://github.com/anishkny [@​harrysarson]: https://github.com/harrysarson ---

Commits

#### v5.0.3 - [`bdcb3c3`](https://github.com/mochajs/mocha/commit/bdcb3c371b2261101609b8c5feb4c6eb539223fb) exposes generateDiff function from base reporter - [`660bccc`](https://github.com/mochajs/mocha/commit/660bcccdb70282cd160c2e18d750fc1dbe2f6a34) adds unit tests covering Base.generateDiff - [`8df5727`](https://github.com/mochajs/mocha/commit/8df5727478a1a9294045ace7d67c4d192ee5dda0) Tidies up code after review - [`aaaa5ab`](https://github.com/mochajs/mocha/commit/aaaa5abdd72e6d9db446c3c0d414947241ce6042) fix: ReDoS vuln in mocha@​5.0.2 › diff@​3.3.1 (#​3266) - [`70d9262`](https://github.com/mochajs/mocha/commit/70d9262d0f13906734e87e33f99afe3f4d61dff8) update CHANGELOG.md for v5.0.3 [ci skip] - [`da6e5c9`](https://github.com/mochajs/mocha/commit/da6e5c967af4284c48ebd35adebdf5c76d1becd1) Release v5.0.3

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This PR has been generated by Renovate Bot.

[coveralls]

Coverage remained the same at 100.0% when pulling 7a1a2c82e5d455b3356c4528676da4f2d21d0baa on renovate/mocha-5.x into bed8748060544ef39491d60dadce723275b05dd3 on master.