level -> label (#3477)
level -> label (#3477)

As noted by @plroebuck `level` is not used, should be `label` instead.

https://github.com/mochajs/mocha/commit/37193a432119be643b9476f97da557a6f60b7d0f#commitcomment-30530038
boneskull/mocha,adamgruber/mocha,mochajs/mocha,mochajs/mocha,igwejk/mocha,boneskull/mocha,outsideris/mocha,adamgruber/mocha,boneskull/mocha,mochajs/mocha,adamgruber/mocha,igwejk/mocha,outsideris/mocha