chore: Bump graphql from 2.1.13 to 2.1.15 (#2389)

Bumps [graphql](https://github.com/rmosolgo/graphql-ruby) from 2.1.13 to 2.1.15.
- [Release notes](https://github.com/rmosolgo/graphql-ruby/releases)
- [Changelog](https://github.com/rmosolgo/graphql-ruby/blob/master/CHANGELOG.md)
- [Commits](rmosolgo/graphql-ruby@v2.1.13...v2.1.15)

---
updated-dependencies:
- dependency-name: graphql
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Gemfile.lock

@@ -361,7 +361,7 @@ GEM
       grape-swagger (>= 1.2.0)
     grape-swagger-rails (0.5.0)
       railties (>= 6.0.6.1)
-    graphql (2.1.13)
+    graphql (2.1.15)
       racc (~> 1.4)
     haml (6.3.0)
       temple (>= 0.8.2)