chore(deps): Ruby > 2.4 EOL

.rubocop.yml

@@ -5,7 +5,7 @@ inherit_gem:
   rubocop-jekyll: .rubocop.yml
 
 AllCops:
-  TargetRubyVersion: 2.3
+  TargetRubyVersion: 2.4
   Exclude:
     - vendor/**/*
 
@@ -14,6 +14,6 @@ Layout/LineLength:
     - spec/**/*
     - jekyll-seo-tag.gemspec
 
-Layout/BlockLength:
+Metrics/BlockLength:
   Exclude:
     - spec/**/*

jekyll-seo-tag.gemspec

@@ -19,14 +19,14 @@ Gem::Specification.new do |spec|
     raise "RubyGems 2.0 or newer is required to protect against public gem pushes."
   end
 
-  spec.required_ruby_version = ">= 2.3.0"
+  spec.required_ruby_version = ">= 2.4.0"
 
   spec.files         = `git ls-files -z`.split("\x0").reject { |f| f.match(%r!^(test|spec|features)/!) }
   spec.bindir        = "exe"
   spec.executables   = spec.files.grep(%r!^exe/!) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
-  spec.add_dependency "jekyll", ">= 3.3", "< 5.0"
+  spec.add_dependency "jekyll", ">= 3.8", "< 5.0"
   spec.add_development_dependency "bundler", ">= 1.15"
   spec.add_development_dependency "html-proofer", "~> 3.7"
   spec.add_development_dependency "rspec", "~> 3.5"