Set Ruby 2.5 as the minimum version

Author: ekohl

.github/workflows/main.yml

@@ -64,5 +64,8 @@ jobs:
           ruby-version: ${{ matrix.ruby }}
       - name: Install
         run: bundle install
+      - name: Run Rubocop
+        run: bundle exec rubocop --format github
+        if: matrix.ruby == '3.1'
       - name: Run tests
-        run: bundle exec rake
+        run: bundle exec rake test

vagrant/Rakefile

@@ -13,8 +13,7 @@ default_tasks = %i[test]
 begin
   require 'rubocop/rake_task'
   RuboCop::RakeTask.new
-  # insert 0, because Ruby 2.0 doesn't know Array.prepend
-  default_tasks.insert(0, 'rubocop')
+  default_tasks.prepend('rubocop')
 rescue LoadError
   puts 'Rubocop not loaded'
 end