Bump notifications-ruby-client from 6.1.0 to 6.2.0

Bumps [notifications-ruby-client](https://github.com/alphagov/notifications-ruby-client) from 6.1.0 to 6.2.0.
- [Changelog](https://github.com/alphagov/notifications-ruby-client/blob/main/CHANGELOG.md)
- [Commits](alphagov/notifications-ruby-client@6.1.0...6.2.0)

---
updated-dependencies:
- dependency-name: notifications-ruby-client
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Gemfile.lock

@@ -301,7 +301,7 @@ GEM
       racc (~> 1.4)
     nokogiri (1.16.7-x86_64-linux)
       racc (~> 1.4)
-    notifications-ruby-client (6.1.0)
+    notifications-ruby-client (6.2.0)
       jwt (>= 1.5, < 3)
     null_logger (0.0.1)
     oauth2 (2.0.9)