Bump mocha from 1.8.0 to 1.9.0

Bumps [mocha](https://github.com/freerange/mocha) from 1.8.0 to 1.9.0.
- [Release notes](https://github.com/freerange/mocha/releases)
- [Changelog](https://github.com/freerange/mocha/blob/master/RELEASE.md)
- [Commits](freerange/mocha@v1.8.0...v1.9.0)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

Gemfile.lock

@@ -178,7 +178,7 @@ GEM
       builder
       minitest (>= 5.0)
       ruby-progressbar
-    mocha (1.8.0)
+    mocha (1.9.0)
       metaclass (~> 0.0.1)
     multipart-post (2.1.1)
     netrc (0.11.0)