Build(deps): Bump minitest from 5.18.1 to 5.19.0 in /Builder

Bumps [minitest](https://github.com/minitest/minitest) from 5.18.1 to 5.19.0.
- [Changelog](https://github.com/minitest/minitest/blob/master/History.rdoc)
- [Commits](minitest/minitest@v5.18.1...v5.19.0)

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

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

Builder/Gemfile.lock

@@ -125,7 +125,7 @@ GEM
     mini_magick (4.12.0)
     mini_mime (1.1.2)
     mini_portile2 (2.8.4)
-    minitest (5.18.1)
+    minitest (5.19.0)
     msgpack (1.7.2)
     net-imap (0.3.7)
       date