Fix compatibility issues with sidekiq-cron 2.2.0 (#2591)

* Update to support Sidekiq::Cron 2.2

Since Sidekiq::Cron 2.2.0, `Sidekiq::Cron::Support.constantize` is removed
and `Sidekiq::Cron::Support.safe_constantize` is added.

We need to check the method is available before calling it.

Related PR: sidekiq-cron/sidekiq-cron#541

* Update changelog

Author: st0012

CHANGELOG.md

@@ -11,6 +11,7 @@
   - Fixes [#2376](https://github.com/getsentry/sentry-ruby/issues/2376)
 - Fix breadcrumb serialization error message to be an object ([#2584](https://github.com/getsentry/sentry-ruby/pull/2584))
   - Fixes [#2478](https://github.com/getsentry/sentry-ruby/issues/2478)
+- Fix compatibility issues with sidekiq-cron 2.2.0 ([#2591](https://github.com/getsentry/sentry-ruby/pull/2591))
 
 ### Internal
 

sentry-sidekiq/lib/sentry/sidekiq/cron/job.rb

@@ -45,11 +45,17 @@ def save
           # fail gracefully if can't find class
           klass_const =
             begin
-              ::Sidekiq::Cron::Support.constantize(klass.to_s)
+              if ::Sidekiq::Cron::Support.respond_to?(:safe_constantize)
+                ::Sidekiq::Cron::Support.safe_constantize(klass.to_s)
+              else
+                ::Sidekiq::Cron::Support.constantize(klass.to_s)
+              end
             rescue NameError
               return true
             end
 
+          return true if klass_const.nil? # Sidekiq::Cron returns nil if class is not found
+
           # only patch if not explicitly included in job by user
           unless klass_const.send(:ancestors).include?(Sentry::Cron::MonitorCheckIns)
             klass_const.send(:include, Sentry::Cron::MonitorCheckIns)