Bump mocha from 1.15.0 to 1.16.0

Bumps [mocha](https://github.com/freerange/mocha) from 1.15.0 to 1.16.0.
- [Release notes](https://github.com/freerange/mocha/releases)
- [Changelog](https://github.com/freerange/mocha/blob/v1.16.0/RELEASE.md)
- [Commits](freerange/mocha@v1.15.0...v1.16.0)

---
updated-dependencies:
- dependency-name: mocha
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

Gemfile.lock

@@ -200,7 +200,7 @@ GEM
       builder
       minitest (>= 5.0)
       ruby-progressbar
-    mocha (1.15.0)
+    mocha (1.16.0)
     net-imap (0.3.1)
       net-protocol
     net-pop (0.1.2)