update rubocop

fix error on ruby 3.4 (require 'base64')

Author: kzkn

rufo.gemspec

@@ -30,7 +30,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "rexml", "~> 3.2.5"
   spec.add_development_dependency "rspec", "~> 3.0"
   spec.add_development_dependency "rspec_junit_formatter", "~> 0.6.0"
-  spec.add_development_dependency "rubocop", "~> 1.44.1"
+  spec.add_development_dependency "rubocop", "~> 1.69.2"
   spec.add_development_dependency "simplecov", "~> 0.22.0"
   spec.add_development_dependency "simplecov-cobertura", "~> 2.1"
 end