Bump rspec-openapi from 0.8.1 to 0.9.0

Bumps [rspec-openapi](https://github.com/exoego/rspec-openapi) from 0.8.1 to 0.9.0.
- [Release notes](https://github.com/exoego/rspec-openapi/releases)
- [Changelog](https://github.com/exoego/rspec-openapi/blob/master/CHANGELOG.md)
- [Commits](exoego/rspec-openapi@v0.8.1...v0.9.0)

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

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

Gemfile.lock

@@ -335,7 +335,7 @@ GEM
     rexml (3.2.6)
     rspec-core (3.12.2)
       rspec-support (~> 3.12.0)
-    rspec-openapi (0.8.1)
+    rspec-openapi (0.9.0)
       actionpack (>= 5.2.0)
       rspec-core
     rspec-support (3.12.1)