(maint) Require vcr 6.1 - 6.x

Specs generated a warning due to an issue with vcr < 6.1 on Ruby 3.1+.
See vcr/vcr@98cc00b

However, vcr 6.1.0 also dropped Ruby 2.5 support, so make the
development dependency conditional based on RUBY_VERSION.

Author: joshcooper

Gemfile

@@ -41,7 +41,7 @@ group(:test) do
   gem "rspec", "~> 3.1", require: false
   gem "rspec-expectations", ["~> 3.9", "!= 3.9.3"]
   gem "rspec-its", "~> 1.1", require: false
-  gem 'vcr', '~> 5.0', require: false
+  gem 'vcr', RUBY_VERSION.to_f >= 3.2 ? '~> 6.1' : '~> 5.0', require: false
   gem 'webmock', '~> 3.0', require: false
   gem 'webrick', '~> 1.7', require: false if RUBY_VERSION.to_f >= 3.0
   gem 'yard', require: false