Bump minitest from 5.15.0 to 5.16.0

Bumps [minitest](https://github.com/seattlerb/minitest) from 5.15.0 to 5.16.0.
- [Release notes](https://github.com/seattlerb/minitest/releases)
- [Changelog](https://github.com/minitest/minitest/blob/master/History.rdoc)
- [Commits](minitest/minitest@v5.15.0...v5.16.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Gemfile.lock

@@ -13,7 +13,7 @@ GEM
     haml (5.2.2)
       temple (>= 0.8.0)
       tilt
-    minitest (5.15.0)
+    minitest (5.16.0)
     prettier_print (0.1.0)
     rake (13.0.6)
     simplecov (0.21.2)