Add upgrade instructions for Sidekiq 7

CHANGELOG.md

@@ -2,7 +2,11 @@
 
 * Switch from using `redis` gem to `redis-client`
 * BREAKING: Remove `redis-namespace` dependency and support for Redis namespaces
-* BREAKING: Upgrade Sidekiq to version 7.0
+* BREAKING: Upgrade Sidekiq to version 7.0, follow these steps to upgrade:
+  1. `Sidekiq::Worker` has been deprecated in Sidekiq 7. Replace all instances of `Sidekiq::Worker` with `Sidekiq::Job`, then rename/move your workers to be `app/sidekiq/MyJob.rb` instead of `app/workers/MyWorker.rb`.
+  1. Remove the requirement for Sidekiq strict arguments from `config/initializers/sidekiq.rb`. This was added to include Sidekiq 7 strict arguments behaviour in Sidekiq 6, but is no longer needed to be explictly required, since this is now the default behaviour.
+  1. If using `sidekiq-unique-jobs`, pin to < 8.0.8 until [a known issue](https://github.com/mhenrixon/sidekiq-unique-jobs/issues/846) is resolved.
+  1. Make any changes required based on the information in the [Sidekiq 7 API migration guide](https://github.com/sidekiq/sidekiq/blob/main/docs/7.0-API-Migration.md).
 
 # 8.0.1