Remove depracated tld_length config option:

tld_length was removed in influitive/apartment#309 , this configuration option doesn't have any effect now.

lib/apartment.rb

@@ -25,7 +25,7 @@ class << self
 
     WRITER_METHODS = %i[tenant_names database_schema_file excluded_models
                         default_schema persistent_schemas connection_class
-                        tld_length db_migrate_tenants seed_data_file
+                        db_migrate_tenants seed_data_file
                         parallel_migration_threads pg_excluded_names].freeze
 
     attr_accessor(*ACCESSOR_METHODS)
@@ -54,6 +54,10 @@ def tenants_with_config
       extract_tenant_config
     end
 
+    def tld_length=(_)
+      Apartment::Deprecation.warn('`config.tld_length` have no effect because it was removed in https://github.com/influitive/apartment/pull/309')
+    end
+
     def db_config_for(tenant)
       (tenants_with_config[tenant] || connection_config)
     end