Add base64 and logger as a development dependencies

Since Ruby 3.4, the gem `base64` is a "bundled" gem, instead of a "default" gem, and needs to be added to the Gemfile.

It is used in the `aws-sdk-cloudformation` gem, but they have not added it as a dependency to not break running older versions of Ruby, therefore we don't add it as a runtime dependency here either.

Similar situation with `logger` which will be removed in Ruby 3.5.

Author: stenlarsson

cuffsert.gemspec

@@ -23,8 +23,10 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency 'ruby-termios'
   spec.add_runtime_dependency 'rx'
 
+  spec.add_development_dependency 'base64'
   spec.add_development_dependency 'bundler', '~> 2.3'
   spec.add_development_dependency 'byebug'
+  spec.add_development_dependency 'logger'
   spec.add_development_dependency 'rspec', '~> 3.0'
   spec.add_development_dependency 'rx-rspec', '~> 0.4.3'
   spec.add_development_dependency 'simplecov'