set sidekiq_options retry to 3 for the GenericWorker (#2052)

Pretty straight forward. Sets the maximum retry count to 3.

Note
We want to add custom retry logic, but that works differently between Sidekiq 5 and 6.
So we think it is better to focus later on the Sidekiq upgrade, and until there, worker instances can handle their exceptions instead of relying on the generic worker for that.

References: 5120, #2005
PR: 2052

app/workers/generic_worker.rb

@@ -2,6 +2,8 @@ class GenericWorker
 
   include Sidekiq::Worker
 
+  sidekiq_options retry: 3
+
   def perform(klass_name, klass_method, *method_args)
     klass = klass_name.constantize
     options = method_args.extract_options!.with_indifferent_access