Use ruby 2.7.1

Author: androse

.github/workflows/test.yml

@@ -15,6 +15,8 @@ jobs:
 
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 2.7.1
 
       - name: Install Ruby Dependencies
         run: bundle install --path vendor/bundle