Bump appraisal from 2.4.1 to 2.5.0

Bumps [appraisal](https://github.com/thoughtbot/appraisal) from 2.4.1 to 2.5.0.
- [Release notes](https://github.com/thoughtbot/appraisal/releases)
- [Commits](thoughtbot/appraisal@v2.4.1...v2.5.0)

---
updated-dependencies:
- dependency-name: appraisal
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Gemfile.lock

@@ -40,7 +40,7 @@ GEM
       minitest (>= 5.1)
       mutex_m
       tzinfo (~> 2.0)
-    appraisal (2.4.1)
+    appraisal (2.5.0)
       bundler
       rake
       thor (>= 0.14.0)