Drop Ruby 2.6 runtime support

This PR drops Ruby 2.6 runtime support. The next release will be the time to drop Ruby 2.6 support:

https://www.ruby-lang.org/en/downloads/branches/
https://docs.rubocop.org/rubocop/compatibility.html#support-matrix

Follow up: rubocop/rubocop#11791

Author: ydah

.github/workflows/main.yml

@@ -27,7 +27,6 @@ jobs:
     strategy:
       matrix:
         ruby:
-          - "2.6"
           - "2.7"
           - "3.0"
           - "3.1"

.rubocop.yml

@@ -8,7 +8,7 @@ require:
 
 AllCops:
   DisplayCopNames: true
-  TargetRubyVersion: 2.6
+  TargetRubyVersion: 2.7
   NewCops: disable
   Exclude:
     - 'vendor/**/*'

CHANGELOG.md

@@ -6,6 +6,7 @@
 - Fix an error for `RSpec/Rails/HaveHttpStatus` with comparison with strings containing non-numeric characters. ([@ydah])
 - Fix an error for `RSpec/MatchArray` when `match_array` with no argument. ([@ydah])
 - Add support `a_block_changing` and `changing` for `RSpec/ChangeByZero`. ([@ydah])
+- Drop Ruby 2.6 support. ([@ydah])
 
 ## 2.20.0 (2023-04-18)
 

rubocop-rspec.gemspec

@@ -21,7 +21,7 @@ Gem::Specification.new do |spec|
 
   spec.version = RuboCop::RSpec::Version::STRING
   spec.platform = Gem::Platform::RUBY
-  spec.required_ruby_version = '>= 2.6.0'
+  spec.required_ruby_version = '>= 2.7.0'
 
   spec.require_paths = ['lib']
   spec.files = Dir[