CI: Add Ruby 4.0

Author: minad

.github/workflows/test.yml

@@ -14,7 +14,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ['2.5', '2.6', '2.7', '3.0', '3.1', '3.2', '3.3', '3.4']
+        ruby: ['2.5', '2.6', '2.7', '3.0', '3.1', '3.2', '3.3', '3.4', '4.0']
     steps:
       - uses: actions/checkout@v4
       - name: Set up Ruby

Gemfile

@@ -2,6 +2,8 @@ source 'https://rubygems.org/'
 
 gemspec
 
+gem 'logger', '~> 1.7'
+gem 'ostruct', '~> 0.6'
 gem 'minitest', '~> 5.15'
 gem 'rake', '~> 13.3'
 gem 'kramdown', '~> 2.5'