Bump shoulda-matchers from 5.1.0 to 6.4.0

Bumps [shoulda-matchers](https://github.com/thoughtbot/shoulda-matchers) from 5.1.0 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@v5.1.0...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.lock

@@ -239,7 +239,6 @@ GEM
     matrix (0.4.2)
     method_source (1.1.0)
     mini_mime (1.1.5)
-    mini_portile2 (2.8.7)
     minitest (5.25.1)
     msgpack (1.7.3)
     mysql2 (0.5.6)
@@ -255,9 +254,6 @@ GEM
     net-smtp (0.5.0)
       net-protocol
     nio4r (2.7.3)
-    nokogiri (1.16.7)
-      mini_portile2 (~> 2.8.2)
-      racc (~> 1.4)
     nokogiri (1.16.7-aarch64-linux)
       racc (~> 1.4)
     nokogiri (1.16.7-arm-linux)
@@ -391,7 +387,7 @@ GEM
     sentry-sidekiq (5.19.0)
       sentry-ruby (~> 5.19.0)
       sidekiq (>= 3.0)
-    shoulda-matchers (5.1.0)
+    shoulda-matchers (6.4.0)
       activesupport (>= 5.2.0)
     sidekiq (7.3.2)
       concurrent-ruby (< 2)
@@ -455,7 +451,6 @@ PLATFORMS
   aarch64-linux
   arm-linux
   arm64-darwin
-  ruby
   x86-linux
   x86_64-darwin
   x86_64-linux
@@ -495,7 +490,6 @@ DEPENDENCIES
   rspec-rails
   rubocop-rails-omakase
   rubocop-rspec
-  sassc-rails
   sentry-sidekiq
   shoulda-matchers
   sidekiq