style: target Ruby 2.4

.rubocop.yml

@@ -3,6 +3,7 @@ inherit_gem:
   rubocop-jekyll: .rubocop.yml
 
 AllCops:
+  TargetRubyVersion: 2.4
   Exclude:
     - vendor/**/*
 Metrics/BlockLength:

jekyll-mentions.gemspec

@@ -14,7 +14,7 @@ Gem::Specification.new do |s|
   s.licenses    = ["MIT"]
   s.files       = ["lib/jekyll-mentions.rb"]
 
-  s.required_ruby_version = ">= 2.3.0"
+  s.required_ruby_version = ">= 2.4.0"
 
   s.add_dependency "html-pipeline", "~> 2.3"
   s.add_dependency "jekyll", ">= 3.7", "< 5.0"

lib/jekyll-mentions.rb

@@ -27,12 +27,12 @@ def mentionify(doc)
           head, opener, tail  = content.partition(OPENING_BODY_TAG_REGEX)
           body_content, *rest = tail.partition("</body>")
 
-          return unless body_content =~ filter_regex
+          return unless body_content&.match?(filter_regex)
 
           processed_markup = filter_with_mention(src).call(body_content)[:output].to_s
           doc.output       = String.new(head) << opener << processed_markup << rest.join
         else
-          return unless content =~ filter_regex
+          return unless content&.match?(filter_regex)
 
           doc.output = filter_with_mention(src).call(content)[:output].to_s
         end