Bump shoulda-matchers from 5.3.0 to 6.4.0

Bumps [shoulda-matchers](https://github.com/thoughtbot/shoulda-matchers) from 5.3.0 to 6.4.0.
- [Release notes](https://github.com/thoughtbot/shoulda-matchers/releases)
- [Changelog](https://github.com/thoughtbot/shoulda-matchers/blob/main/CHANGELOG.md)
- [Commits](thoughtbot/shoulda-matchers@v5.3.0...v6.4.0)

---
updated-dependencies:
- dependency-name: shoulda-matchers
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile

@@ -90,7 +90,7 @@ group :test do
   gem "faker"
   gem "rspec"
   gem "rspec-rails"
-  gem "shoulda-matchers", "~> 5.3"
+  gem "shoulda-matchers", "~> 6.4"
   gem "vcr", "~> 6.2"
   gem "webmock", "~> 3.18"
 end

Gemfile.lock

@@ -445,7 +445,7 @@ GEM
       sentry-ruby (~> 5.10.0)
     sentry-ruby (5.10.0)
       concurrent-ruby (~> 1.0, >= 1.0.2)
-    shoulda-matchers (5.3.0)
+    shoulda-matchers (6.4.0)
       activesupport (>= 5.2.0)
     sidekiq (6.5.12)
       connection_pool (>= 2.2.5, < 3)
@@ -592,7 +592,7 @@ DEPENDENCIES
   rspec-rails
   rubocop-govuk
   sentry-rails
-  shoulda-matchers (~> 5.3)
+  shoulda-matchers (~> 6.4)
   sidekiq (< 7)
   sidekiq-cron (~> 1.10)
   solargraph