Update Travis Xcode images to 12.2

Update to bundler 2.0 in gempsec

.travis.yml

@@ -1,10 +1,10 @@
 language: objective-c
 script: bundle exec rake
-osx_image: xcode9.2
+osx_image: xcode12.2
 
 before_install:
   - curl http://curl.haxx.se/ca/cacert.pem -o /usr/local/share/cacert.pem
-  - gem install bundler -v "~> 1.0" --no-ri --no-rdoc
+  - gem install bundler -v "~> 2.0" --no-document
 
 install:
   - bundle install --without=documentation

slather.gemspec

@@ -17,7 +17,7 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ['lib']
 
-  spec.add_development_dependency 'bundler', '~> 1.17'
+  spec.add_development_dependency 'bundler', '~> 2.0'
   spec.add_development_dependency 'coveralls', '~> 0.8'
   spec.add_development_dependency 'simplecov', '~> 0'
   spec.add_development_dependency 'rake', '~> 12.3'