ruby updated to 3.1, #235

Author: Intelligent2013

.github/workflows/test.yml

@@ -36,7 +36,7 @@ jobs:
 
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 2.7
+          ruby-version: 3.1
 
       - if: matrix.os == 'ubuntu-latest'
         run: sudo gem install fontist