Bump the rails_61 group in /gemfiles/rails_61 with 1 update

Bumps the rails_61 group in /gemfiles/rails_61 with 1 update: [minitest](https://github.com/minitest/minitest).


Updates `minitest` from 5.20.0 to 5.21.2
- [Changelog](https://github.com/minitest/minitest/blob/master/History.rdoc)
- [Commits](minitest/minitest@v5.20.0...v5.21.2)

---
updated-dependencies:
- dependency-name: minitest
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: rails_61
...

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

gemfiles/rails_61/Gemfile.lock

@@ -96,7 +96,7 @@ GEM
     method_source (1.0.0)
     mini_mime (1.1.5)
     mini_portile2 (2.8.5)
-    minitest (5.20.0)
+    minitest (5.21.2)
     minitest-reporters (1.6.1)
       ansi
       builder