Ruby minimum version increase followup (#819)

.travis.yml

@@ -23,8 +23,6 @@ cache:
  - stripe-mock
 
 before_install:
- # Install bundler 1.x, because we need to support Ruby 2.1 for now
- - gem install bundler -v "~> 1.0"
  # Unpack and start stripe-mock so that the test suite can talk to it
  - |
  if [ ! -d "stripe-mock/stripe-mock_${STRIPE_MOCK_VERSION}" ]; then

Gemfile

@@ -7,6 +7,7 @@ gemspec
 group :development do
  gem "coveralls", require: false
  gem "mocha", "~> 0.13.2"
+ gem "rack", ">= 2.0.6"
  gem "rake"
  gem "shoulda-context"
  gem "test-unit"
@@ -20,15 +21,6 @@ group :development do
  # up-to-date, but it's not the end of the world if it's not.
  gem "rubocop", "0.73"
 
- # Rack 2.0+ requires Ruby >= 2.2.2 which is problematic for the test suite on
- # older Ruby versions. Check Ruby the version here and put a maximum
- # constraint on Rack if necessary.
- if RUBY_VERSION >= "2.2.2"
- gem "rack", ">= 2.0.6"
- else
- gem "rack", ">= 1.6.11", "< 2.0" # rubocop:disable Bundler/DuplicatedGem
- end
-
  platforms :mri do
  gem "byebug"
  gem "pry"

README.md

@@ -39,7 +39,7 @@ gem build stripe.gemspec
 
 ### Requirements
 
-- Ruby 2.1+.
+- Ruby 2.3+.
 
 ### Bundler