Bump rack from 2.2.3 to 2.2.6.3 in /graphql

Bumps [rack](https://github.com/rack/rack) from 2.2.3 to 2.2.6.3.
- [Release notes](https://github.com/rack/rack/releases)
- [Changelog](https://github.com/rack/rack/blob/main/CHANGELOG.md)
- [Commits](rack/rack@2.2.3...v2.2.6.3)

---
updated-dependencies:
- dependency-name: rack
  dependency-type: indirect
...

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

Author: dependabot[bot]

graphql/Gemfile.lock

@@ -5,7 +5,7 @@ GEM
     multi_json (1.15.0)
     mustermann (1.1.1)
       ruby2_keywords (~> 0.0.1)
-    rack (2.2.3)
+    rack (2.2.6.3)
     rack-contrib (2.3.0)
       rack (~> 2.0)
     rack-graphiql (0.1.1)