Naming/VariableNumber reporting on stdlib call

[mmainz]

I have the following code:

        if serialized_value.respond_to?(:iso8601)

---

Expected behavior

I'd expect this to not yield an offense. The method is called iso8601 and I am not able to change that, since the Time class is from the standard lib. So I have no way of fixing the issue. And I don't want to litter my code with comments to disable Rubocop every time this is done.

Actual behavior

Inspecting 85 files
...............................C.....................................................
Offenses:
lib/serializers/merged_queue_serializer.rb:25:41: C: Naming/VariableNumber: Use snake_case for symbol numbers.
        if serialized_value.respond_to?(:iso8601)
                                        ^^^^^^^^
85 files inspected, 1 offense detected

RuboCop version

1.4.2 (using Parser 2.7.2.0, rubocop-ast 1.2.0, running on ruby 2.7.2 x86_64-darwin19)
  - rubocop-rspec 2.0.0