ArgumentError when proxying association method_missing under Ruby 3 due to improper kwarg handling

[xeger]

I have a fix that handles SingleAssociation. I looked into fixing ManyAssociation too but I'm not sure it's warranted; Array doesn't make use of keyword args, so it would be awkward to test.

STR:

class Foo
  include Dynamoid::Document
  belongs_to :bar
end

class Bar
  include Dynamoid::Document

  def baz(kwarg1:, kwarg2:)
  end
end

# load a model
foo = ::Foo.find(foo_key, raise_error: false, consistent_read: true)

# follow a belongs_to association to a related model
bar = foo.bar

# call instance method of related model; will be proxied by Dynamoid::Associations::BelongsTo
bar.baz(kwarg1: 'hi')

Expected outcome: method is proxied faithfully to Bar#baz.

Actual outcome: keyword args are transformed into a hash that is passed as a positional arg

ArgumentError: wrong number of arguments (given 1, expected 0; required keywords: kwarg1, kwarg2)