Remove ruby-version mention from linting.yml

Author: george-ma

.github/workflows/linting.yml

@@ -9,7 +9,6 @@ jobs:
     - uses: actions/checkout@v3
     - uses: ruby/setup-ruby@v1
       with:
-        ruby-version: '3.0'
         bundler-cache: true # runs 'bundle install' and caches installed gems automatically
     - name: Rubocop
       run: bundle exec rubocop