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

@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby: [ '2.5', '2.6', '2.7', '3.0', '3.1', '3.2', '3.3' ]
+        ruby: [ '2.7', '3.0', '3.1', '3.2', '3.3' ]
     name: Ruby ${{ matrix.ruby }}
     steps:
       - uses: actions/checkout@v2

.gitignore

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

.rubocop.yml

@@ -1,6 +1,3 @@
-AllCops:
-  TargetRubyVersion: 2.3
-
 Metrics/LineLength:
   Max: 120
 

.ruby-version

@@ -0,0 +1 @@
+2.7.5

Gemfile.lock

@@ -0,0 +1,82 @@
+PATH
+  remote: .
+  specs:
+    buildkit (1.5.0)
+      sawyer (>= 0.6)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    addressable (2.8.6)
+      public_suffix (>= 2.0.2, < 6.0)
+    ast (2.4.2)
+    base64 (0.2.0)
+    byebug (11.1.3)
+    diff-lcs (1.5.1)
+    faraday (2.8.1)
+      base64
+      faraday-net_http (>= 2.0, < 3.1)
+      ruby2_keywords (>= 0.0.4)
+    faraday-net_http (3.0.2)
+    json (2.7.1)
+    language_server-protocol (3.17.0.3)
+    parallel (1.24.0)
+    parser (3.3.0.5)
+      ast (~> 2.4.1)
+      racc
+    public_suffix (5.0.5)
+    racc (1.7.3)
+    rainbow (3.1.1)
+    rake (13.2.0)
+    regexp_parser (2.9.0)
+    rexml (3.2.6)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.0)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.1)
+    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)
+    ruby-progressbar (1.13.0)
+    ruby2_keywords (0.0.5)
+    sawyer (0.9.2)
+      addressable (>= 2.3.5)
+      faraday (>= 0.17.3, < 3)
+    unicode-display_width (2.5.0)
+    vcr (3.0.3)
+    yard (0.9.36)
+
+PLATFORMS
+  arm64-darwin-23
+
+DEPENDENCIES
+  buildkit!
+  bundler
+  byebug
+  rake
+  rspec (~> 3.2)
+  rubocop (~> 1.61.0)
+  vcr (~> 3.0)
+  yard
+
+BUNDLED WITH
+   2.4.18

buildkit.gemspec

@@ -21,7 +21,7 @@ Gem::Specification.new do |spec|
 
   spec.metadata['allowed_push_host'] = 'https://rubygems.org'
 
-  spec.required_ruby_version = '>= 2.3'
+  spec.required_ruby_version = '>= 2.7'
 
   spec.add_dependency 'sawyer', '>= 0.6'
   spec.add_development_dependency 'bundler'

dev.yml

@@ -3,7 +3,7 @@ name: buildkit
 type: ruby
 
 up:
-  - ruby: 2.5.5
+  - ruby
   - bundler
 
 commands: