Drop support for Ruby 2.1 and 2.2 (#6560)

Merge pull request 6560

.rubocop.yml

@@ -8,7 +8,7 @@ Jekyll/NoPutsAllowed:
     - rake/*.rake
 
 AllCops:
-  TargetRubyVersion: 2.1
+  TargetRubyVersion: 2.3
   Include:
     - lib/**/*.rb
   Exclude:
@@ -53,6 +53,8 @@ Layout/EmptyComment:
   Enabled: false
 Layout/EndAlignment:
   Severity: error
+Lint/UnneededRequireStatement:
+  Enabled: false
 Lint/UnreachableCode:
   Severity: error
 Lint/UselessAccessModifier:
@@ -105,6 +107,8 @@ Naming/MemoizedInstanceVariableName:
 Naming/UncommunicativeMethodParamName:
   AllowedNames:
     - _
+Performance/UnfreezeString:
+  Enabled: false
 Security/MarshalLoad:
   Exclude:
     - !ruby/regexp /test\/.*.rb$/
@@ -148,6 +152,8 @@ Style/ModuleFunction:
   Enabled: false
 Style/MultilineTernaryOperator:
   Severity: error
+Style/NumericPredicate:
+  Enabled: false
 Style/PercentLiteralDelimiters:
   PreferredDelimiters:
     "%q": "{}"
@@ -157,6 +163,8 @@ Style/PercentLiteralDelimiters:
     "%w": "()"
     "%W": "()"
     "%x": "()"
+Style/RedundantFreeze:
+  Enabled: false
 Style/RedundantReturn:
   Enabled: false
 Style/RedundantSelf:
@@ -165,6 +173,8 @@ Style/RegexpLiteral:
   EnforcedStyle: percent_r
 Style/RescueModifier:
   Enabled: false
+Style/SafeNavigation:
+  Enabled: false
 Style/SignalException:
   EnforcedStyle: only_raise
 Style/SingleLineMethods:

.travis.yml

@@ -8,7 +8,6 @@ rvm:
   - &ruby1 2.5.1
   - &ruby2 2.4.4
   - &ruby3 2.3.7
-  - &ruby4 2.2.10
   - &jruby jruby-9.1.16.0
 
 matrix:

Gemfile

@@ -7,9 +7,6 @@ gem "rake", "~> 12.0"
 
 gem "rouge", ENV["ROUGE"] if ENV["ROUGE"]
 
-# Dependency of jekyll-mentions. RubyGems in Ruby 2.1 doesn't shield us from this.
-gem "activesupport", "~> 4.2", :groups => [:test_legacy, :site] if RUBY_VERSION < "2.2.2"
-
 group :development do
   gem "launchy", "~> 2.3"
   gem "pry"
@@ -23,12 +20,11 @@ end
 
 group :test do
   gem "codeclimate-test-reporter", "~> 1.0.5"
-  gem "cucumber", RUBY_VERSION >= "2.2" ? "~> 3.0" : "3.0.1"
+  gem "cucumber", "~> 3.0"
   gem "httpclient"
   gem "jekyll_test_plugin"
   gem "jekyll_test_plugin_malicious"
-  # nokogiri v1.8 does not work with ruby 2.1 and below
-  gem "nokogiri", RUBY_VERSION >= "2.2" ? "~> 1.7" : "~> 1.7.0"
+  gem "nokogiri", "~> 1.7"
   gem "rspec"
   gem "rspec-mocks"
   gem "rubocop", "~> 0.55.0"
@@ -41,7 +37,7 @@ end
 #
 
 group :test_legacy do
-  if RUBY_PLATFORM =~ %r!cygwin! || RUBY_VERSION.start_with?("2.2")
+  if RUBY_PLATFORM =~ %r!cygwin!
     gem "test-unit"
   end
 

appveyor.yml

@@ -28,8 +28,6 @@ environment:
       TEST_SUITE: "test"
     - RUBY_FOLDER_VER: "23"
       TEST_SUITE: "test"
-    - RUBY_FOLDER_VER: "22"
-      TEST_SUITE: "test"
 
 test_script:
   - ruby --version

jekyll.gemspec

@@ -8,7 +8,7 @@ Gem::Specification.new do |s|
   s.specification_version = 2 if s.respond_to? :specification_version=
   s.required_rubygems_version = Gem::Requirement.new(">= 0") if s.respond_to? :required_rubygems_version=
   s.rubygems_version = "2.2.2"
-  s.required_ruby_version = ">= 2.1.0"
+  s.required_ruby_version = ">= 2.3.0"
 
   s.name          = "jekyll"
   s.version       = Jekyll::VERSION