Bump groupdate from 6.2.1 to 6.4.0

Bumps [groupdate](https://github.com/ankane/groupdate) from 6.2.1 to 6.4.0.
- [Changelog](https://github.com/ankane/groupdate/blob/master/CHANGELOG.md)
- [Commits](https://github.com/ankane/groupdate/compare/v6.2.1...v6.4.0)

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

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

Gemfile

@@ -28,7 +28,7 @@ gem "globalize", "~> 6.2.1"
 gem "globalize-accessors", "~> 0.3.0"
 gem "graphiql-rails", "~> 1.8.0"
 gem "graphql", "~> 1.12.14"
-gem "groupdate", "~> 6.2.1"
+gem "groupdate", "~> 6.4.0"
 gem "image_processing", "~> 1.12.2"
 gem "initialjs-rails", "~> 0.2.0.9"
 gem "invisible_captcha", "~> 2.1.0"