Revert "Drop Ruby 2.7 support as EOL and I have trouble with some deps"

This reverts commit 31eed31.

Author: amatsuda

.github/workflows/stable.yml

@@ -13,6 +13,7 @@ jobs:
 
       matrix:
         ruby-version:
+          - '2.7'
           - '3.0'
           - '3.1'
           - '3.2'

.rubocop.yml

@@ -10,7 +10,7 @@ AllCops:
     - "tmp/**/*"
     - "vendor/bundle/**/*"
     - "vendor/bundle/**/.*"
-  TargetRubyVersion: 3.0
+  TargetRubyVersion: 2.7
   NewCops: enable
   # we might wanna adopt rspec and rake but it's a bit annoying for now
   SuggestExtensions: false

README.md

@@ -889,7 +889,7 @@ SimpleCov.formatter = SimpleCov::Formatter::JSONFormatter
 
 ## Ruby version compatibility
 
-SimpleCov is built in [Continuous Integration] on Ruby 3.0+ as well as JRuby 9.3+.
+SimpleCov is built in [Continuous Integration] on Ruby 2.7+ as well as JRuby 9.3+.
 
 Note for JRuby => You need to pass JRUBY_OPTS="--debug" or create .jrubyrc and add debug.fullTrace=true
 

simplecov.gemspec

@@ -33,7 +33,7 @@ Gem::Specification.new do |gem|
 "rubygems_mfa_required" => "true"
   }
 
-  gem.required_ruby_version = ">= 3.0.0"
+  gem.required_ruby_version = ">= 2.7.0"
 
   gem.add_dependency "docile", "~> 1.1"
   gem.add_dependency "simplecov-html", "~> 0.11"