Remove Rails 4.2 from testing matrix

Author: robzolkos

.travis.yml

@@ -5,8 +5,7 @@ cache:
   bundler: true
 
 before_install:
-  - gem uninstall -v '>= 2' -i $(rvm gemdir)@global -ax bundler || true
-  - gem install bundler -v '<2'
+  - gem install bundler
 
 rvm:
   - 2.4.6

actionpack-page_caching.gemspec

@@ -8,14 +8,14 @@ Gem::Specification.new do |gem|
   gem.homepage      = "https://github.com/rails/actionpack-page_caching"
   gem.license       = "MIT"
 
-  gem.required_ruby_version = '>= 1.9.3'
+  gem.required_ruby_version = '>= 2.4.6'
   gem.files         = `git ls-files`.split($/)
   gem.executables   = gem.files.grep(%r{^bin/}).map { |f| File.basename(f) }
   gem.test_files    = gem.files.grep(%r{^(test|spec|features)/})
   gem.require_paths = ["lib"]
   gem.license       = 'MIT'
 
-  gem.add_dependency "actionpack", ">= 4.0.0"
+  gem.add_dependency "actionpack", ">= 5.0.0"
 
   gem.add_development_dependency "mocha"
 end