fix 3.1 support

Author: npezza93

test/config_stubs.rb

@@ -4,9 +4,9 @@ module ConfigStubs
   extend ActiveSupport::Concern
 
   class ConfigStub
-    def initialize(**)
+    def initialize(**opts)
       @config = ActiveSupport::OrderedOptions.new.
-                update({ adapter: :test }.merge(**))
+                update({ adapter: :test }.merge(**opts))
     end
 
     def config_for(_file)