build(deps): bump minitest from 5.18.0 to 5.18.1

Bumps [minitest](https://github.com/minitest/minitest) from 5.18.0 to 5.18.1.
- [Changelog](https://github.com/minitest/minitest/blob/master/History.rdoc)
- [Commits](minitest/minitest@v5.18.0...v5.18.1)

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

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

Gemfile.lock

@@ -41,7 +41,7 @@ GEM
       rb-inotify (~> 0.9, >= 0.9.10)
     lumberjack (1.2.8)
     method_source (1.0.0)
-    minitest (5.18.0)
+    minitest (5.18.1)
     multi_xml (0.6.0)
     mustermann (3.0.0)
       ruby2_keywords (~> 0.0.1)