Fix standardrb violations

app/controllers/solidus_friendly_promotions/admin/base_controller.rb

@@ -7,7 +7,7 @@ def parent
         @parent ||= self.class.parent_data[:model_class]
           .includes(self.class.parent_data[:includes])
           .find_by!(self.class.parent_data[:find_by] => params["#{parent_model_name}_id"])
-        instance_variable_set("@#{parent_model_name}", @parent)
+        instance_variable_set(:"@#{parent_model_name}", @parent)
       rescue ActiveRecord::RecordNotFound => e
         resource_not_found(flash_class: e.model.constantize, redirect_url: routes_proxy.polymorphic_url([:admin, parent_model_name.pluralize.to_sym]))
       end

app/controllers/solidus_friendly_promotions/admin/promotion_rules_controller.rb

@@ -63,7 +63,7 @@ def model_class
 
       def validate_promotion_rule_type
         requested_type = params[:promotion_rule].delete(:type)
-        promotion_rule_types = SolidusFriendlyPromotions.config.send("#{@level}_rules")
+        promotion_rule_types = SolidusFriendlyPromotions.config.send(:"#{@level}_rules")
         @promotion_rule_type = promotion_rule_types.detect do |klass|
           klass.name == requested_type
         end

app/helpers/solidus_friendly_promotions/admin/promotion_rules_helper.rb

@@ -5,7 +5,7 @@ module Admin
     module PromotionRulesHelper
       def options_for_promotion_rule_types(promotion_rule, level)
         existing = promotion_rule.promotion.rules.select(&:persisted?).map { |rule| rule.class.name }
-        rules = SolidusFriendlyPromotions.config.send("#{level}_rules").reject { |rule| existing.include? rule.name }
+        rules = SolidusFriendlyPromotions.config.send(:"#{level}_rules").reject { |rule| existing.include? rule.name }
         options = rules.map { |rule| [rule.model_name.human, rule.name] }
         options_for_select(options, promotion_rule.type.to_s)
       end

app/models/concerns/solidus_friendly_promotions/rules/line_item_applicable_order_rule.rb

@@ -12,7 +12,7 @@ def applicable?(promotable)
       end
 
       def eligible?(promotable)
-        send("#{promotable.class.name.demodulize.underscore}_eligible?", promotable)
+        send(:"#{promotable.class.name.demodulize.underscore}_eligible?", promotable)
       end
 
       def level

lib/solidus_friendly_promotions/promotion_migrator.rb

@@ -94,7 +94,7 @@ def generate_new_promotion_rules(old_promotion_rule)
       else
         new_rule = new_promo_rule_class.new(old_promotion_rule.attributes.except(*PROMOTION_IGNORED_ATTRIBUTES))
         new_rule.preload_relations.each do |relation|
-          new_rule.send("#{relation}=", old_promotion_rule.send(relation))
+          new_rule.send(:"#{relation}=", old_promotion_rule.send(relation))
         end
         [new_rule]
       end