Bump ransack from 2.3.2 to 2.4.0

Bumps [ransack](https://github.com/activerecord-hackery/ransack) from 2.3.2 to 2.4.0.
- [Release notes](https://github.com/activerecord-hackery/ransack/releases)
- [Changelog](https://github.com/activerecord-hackery/ransack/blob/master/CHANGELOG.md)
- [Commits](https://github.com/activerecord-hackery/ransack/compare/v2.3.2...2.4.0)

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

Gemfile.lock

@@ -239,8 +239,6 @@ GEM
       ast (~> 2.4.1)
     path_expander (1.1.0)
     pg (1.2.3)
-    polyamorous (2.3.2)
-      activerecord (>= 5.2.1)
     pry (0.13.1)
       coderay (~> 1.1)
       method_source (~> 1.0)
@@ -312,11 +310,10 @@ GEM
       thor (>= 0.19.0, < 2.0)
     rainbow (3.0.0)
     rake (13.0.1)
-    ransack (2.3.2)
-      activerecord (>= 5.2.1)
-      activesupport (>= 5.2.1)
+    ransack (2.4.0)
+      activerecord (>= 5.2.4)
+      activesupport (>= 5.2.4)
       i18n
-      polyamorous (= 2.3.2)
     rb-fsevent (0.10.4)
     rb-inotify (0.10.1)
       ffi (~> 1.0)