use ruby version

Author: ka8725

.github/workflows/main.yml

@@ -33,7 +33,8 @@ jobs:
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
         with:
-          bundler-cache: false # runs 'bundle install' and caches installed gems automatically
+          ruby-version: 2.6.10
+          bundler-cache: true # runs 'bundle install' and caches installed gems automatically
           cache-version: 0 # Increment this number if you need to re-download cached gems
       - name: Setup Pages
         id: pages