Bump slack-notifier from 2.3.2 to 2.4.0 (#13705)

Bumps [slack-notifier](https://github.com/stevenosloan/slack-notifier) from 2.3.2 to 2.4.0.
- [Release notes](https://github.com/stevenosloan/slack-notifier/releases)
- [Changelog](https://github.com/slack-notifier/slack-notifier/blob/main/changelog.md)
- [Commits](https://github.com/stevenosloan/slack-notifier/compare/2.3.2...2.4.0)

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

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

Gemfile

@@ -100,7 +100,7 @@ gem "sidekiq", "~> 6.2.1" # Sidekiq is used to process background jobs with the
 gem "sidekiq-cron", "~> 1.1" # Allows execution of scheduled cron jobs as specific times
 gem "sidekiq-unique-jobs", "~> 7.0.9" # Ensures that Sidekiq jobs are unique when enqueued
 gem "sitemap_generator", "~> 6.1" # SitemapGenerator is a framework-agnostic XML Sitemap generator
-gem "slack-notifier", "~> 2.3" # A slim ruby wrapper for posting to slack webhooks
+gem "slack-notifier", "~> 2.4" # A slim ruby wrapper for posting to slack webhooks
 gem "sprockets", "~> 4.0" # Sprockets is a Rack-based asset packaging system
 gem "staccato", "~> 0.5" # Ruby Google Analytics Measurement
 gem "store_attribute", "~> 0.8.1" # ActiveRecord extension which adds typecasting to store accessors.

Gemfile.lock

@@ -738,7 +738,7 @@ GEM
     simplecov_json_formatter (0.1.2)
     sitemap_generator (6.1.2)
       builder (~> 3.0)
-    slack-notifier (2.3.2)
+    slack-notifier (2.4.0)
     smart_properties (1.15.0)
     spring (2.1.1)
     spring-commands-rspec (1.0.4)
@@ -968,7 +968,7 @@ DEPENDENCIES
   sidekiq-unique-jobs (~> 7.0.9)
   simplecov (~> 0.21.2)
   sitemap_generator (~> 6.1)
-  slack-notifier (~> 2.3)
+  slack-notifier (~> 2.4)
   spring (~> 2.1)
   spring-commands-rspec (~> 1.0)
   sprockets (~> 4.0)