Centralize Ruby Version to .ruby-version

The `.ruby-version` file is the ecosystem standard for defining a Ruby version.  This PR adds the `.ruby-version` file, ensures a `required_ruby_version` is set, and removes all other references to Ruby in this repository, aligning it with the standard.
> [!IMPORTANT]
> Please verify the following before merging:

Verify that the changes in the PR meets the following requirements or adjust manually to make it compliant:
  - [ ] `.ruby-version` file is present with the correct Ruby version defined
  - [ ] A `required_ruby_version` in your gemspec is set
  - [ ] There is no Ruby version present in the  `dev.yml` Ruby task (before: `- ruby: x.x.x`, after: `- ruby`)
  - [ ] There is no Ruby version/requirement referenced in the `Gemfile` (no lines with `ruby  <some-version>`)
  - [ ] A `Gemfile.lock` is built with the defined Ruby version
  - [ ] The version of Rubocop installed is 1.61.0 or greater
  - [ ] There is no `TargetRubyVersion` defined  in `rubocop.yml` (reads from  `required_ruby_version` on Rubocop 1.61.0)
  - [ ] There is no Ruby argument  present in  `ruby/setup-ruby` Github Actions that do **not**  run on a Ruby matrix (no lines with `ruby-version: “x.x”`)

To establish consistency, the `required_ruby_version` is set to 2.7. If you think that another version is a better fit, please make the applicable changes.

Please merge this PR if it looks good, this PR will be addressed if there isn't any activity after 4 weeks.

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: [2.7, 3.1, 3.3]
+        ruby: [2.7, 3.0, 3.1, 3.2, 3.3]
         graphql_version: ['~> 1.12.18', '~> 1.13', '~> 2.0']
         include:
           - ruby: 2.4

.gitignore

@@ -1,6 +1,5 @@
 /.bundle/
 /.yardoc
-/Gemfile*.lock
 /_yardoc/
 /coverage/
 /doc/

Gemfile

@@ -3,7 +3,5 @@ source 'https://rubygems.org'
 gemspec
 
 gem 'graphql', ENV['GRAPHQL_VERSION'] if ENV['GRAPHQL_VERSION']
-if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('2.4.0')
-  gem 'rubocop', '~> 1.12.0', require: false
-  gem "rubocop-shopify", '~> 1.0.7', require: false
-end
+gem 'rubocop', '~> 1.61.0', require: false
+gem "rubocop-shopify", require: false

Gemfile.lock

@@ -0,0 +1,60 @@
+PATH
+  remote: .
+  specs:
+    graphql-batch (0.6.0)
+      graphql (>= 1.12.18, < 3)
+      promise.rb (~> 0.7.2)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    ast (2.4.2)
+    base64 (0.2.0)
+    byebug (11.1.3)
+    graphql (2.3.0)
+      base64
+    json (2.7.1)
+    language_server-protocol (3.17.0.3)
+    minitest (5.22.3)
+    parallel (1.24.0)
+    parser (3.3.0.5)
+      ast (~> 2.4.1)
+      racc
+    promise.rb (0.7.4)
+    racc (1.7.3)
+    rainbow (3.1.1)
+    rake (13.2.0)
+    regexp_parser (2.9.0)
+    rexml (3.2.6)
+    rubocop (1.61.0)
+      json (~> 2.3)
+      language_server-protocol (>= 3.17.0)
+      parallel (~> 1.10)
+      parser (>= 3.3.0.2)
+      rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 1.8, < 3.0)
+      rexml (>= 3.2.5, < 4.0)
+      rubocop-ast (>= 1.30.0, < 2.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 2.4.0, < 3.0)
+    rubocop-ast (1.31.2)
+      parser (>= 3.3.0.4)
+    rubocop-shopify (2.15.1)
+      rubocop (~> 1.51)
+    ruby-progressbar (1.13.0)
+    unicode-display_width (2.5.0)
+
+PLATFORMS
+  arm64-darwin-23
+  ruby
+
+DEPENDENCIES
+  byebug
+  graphql-batch!
+  minitest
+  rake (>= 12.3.3)
+  rubocop (~> 1.61.0)
+  rubocop-shopify
+
+BUNDLED WITH
+   2.5.3

graphql-batch.gemspec

@@ -10,6 +10,8 @@ Gem::Specification.new do |spec|
   spec.homepage      = "https://github.com/Shopify/graphql-batch"
   spec.license       = "MIT"
 
+  spec.required_ruby_version = ">= 2.7"
+
   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) }