Drop the support of ruby 2.2

since we encounter Segmentation fault and have no idea how to fix it

The error messages:

Installing Bundler
  /opt/hostedtoolcache/Ruby/2.2.10/x64/bin/gem install bundler -v 1.17.3
  /opt/hostedtoolcache/Ruby/2.2.10/x64/lib/ruby/2.2.0/rubygems/source.rb:192: [BUG] Segmentation fault at 0x00000000000010
  ruby 2.2.10p489 (2018-03-28 revision 63023) [x86_64-linux]

.github/workflows/ruby.yml

@@ -20,7 +20,7 @@ jobs:
  fail-fast: false
  matrix:
  ruby:
- - 2.2
+ - 2.3
  - 2.6
  - 2.7
  - 3.0
@@ -62,11 +62,11 @@ jobs:
  - gemfile: 5.2.gemfile
  ruby: 3.1
  - gemfile: 6.0.gemfile
- ruby: 2.2
+ ruby: 2.3
  - gemfile: 6.1.gemfile
- ruby: 2.2
+ ruby: 2.3
  - gemfile: 7.0.gemfile
- ruby: 2.2
+ ruby: 2.3
  - gemfile: 7.0.gemfile
  ruby: 2.6
  env:

README.md

@@ -11,7 +11,7 @@
 It will use built-in `or` method, which was added in Rails 5, when possible, so that you don't need to worry about that it will polulate `active_model`. Otherwise, it implements `or` method for Rails 3 and Rails 4.
 
 ## Supports
-- Ruby 2.2 ~ 2.7, 3.0 ~ 3.1
+- Ruby 2.3 ~ 2.7, 3.0 ~ 3.1
 - Rails 3.2, 4.2, 5.0, 5.1, 5.2, 6.0, 6.1, 7.0
 
 ## Installation