Bump groupdate from 5.1.0 to 5.2.1

Bumps [groupdate](https://github.com/ankane/groupdate) from 5.1.0 to 5.2.1.
- [Release notes](https://github.com/ankane/groupdate/releases)
- [Changelog](https://github.com/ankane/groupdate/blob/master/CHANGELOG.md)
- [Commits](https://github.com/ankane/groupdate/compare/v5.1.0...v5.2.1)

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

Gemfile.lock

@@ -264,7 +264,7 @@ GEM
     graphiql-rails (1.4.8)
       rails
     graphql (1.7.8)
-    groupdate (5.1.0)
+    groupdate (5.2.1)
       activesupport (>= 5)
     gyoku (1.3.1)
       builder (>= 2.1.2)
@@ -671,7 +671,7 @@ DEPENDENCIES
   globalize-accessors (~> 0.2.1)
   graphiql-rails (~> 1.4.1)
   graphql (~> 1.7.8)
-  groupdate (~> 5.1.0)
+  groupdate (~> 5.2.1)
   i18n-tasks (~> 0.9.31)
   initialjs-rails (~> 0.2.0.9)
   invisible_captcha (~> 0.10.0)