Tighten arity of value and object fields

[Bo98]

Tapioca isn't currently importing all the field signatures correctly. You can see that at kuby-core where in ObjectMeta the annotations signature is imported but most of the others are not: https://github.com/getkuby/kuby-core/blob/master/sorbet/rbi/gems/kube-dsl%400.8.0.rbi#L9080-L9088

This is because Tapioca sees the method definitions having a different parameter signature to the RBIs due to the use of *args. When in this situation, Tapioca currently chooses to ignore the RBI.

To fix this I tightened the arity of value and object fields (i.e. removed *args). I kept backwards compatibility as much as possible except for two small breaks, though they are unlikely to be hit by anyone:

• This now correctly errors at runtime (previously just ignored further arguments):

KubeDSL.namespace do
  metadata do
    name "my-namespace", "other argument"
  end
end

• Object field positional arguments are no longer supported (and never was in RBIs nor the generator anyway):

class Test < KubeDSL::DSLObject
  object_field(:weird_field) { |some_arg| some_arg ? KubeDSL.object_meta : KubeDSL.list_meta }
end

Test.new do
  weird_field(true) do
    puts "1: weird_field(true) = #{self.class}"
  end
end

Test.new do
  weird_field(false) do
    puts "2: weird_field(false) = #{self.class}"
  end

  weird_field(true) do
    # will not change it from false
    puts "2: weird_field(true) = #{self.class}"
  end
end

# OLD BEHAVIOUR:
# 1: weird_field(true) = KubeDSL::DSL::Meta::V1::ObjectMeta
# 2: weird_field(false) = KubeDSL::DSL::Meta::V1::ListMeta
# 2: weird_field(true) = KubeDSL::DSL::Meta::V1::ListMeta

# NEW BEHAVIOUR:
# lib/kube-dsl/value_fields.rb:32:in `block in object_field': wrong number of arguments (given 1, expected 0) (ArgumentError)