add 2.7 & 3.0

Author: semmons99

.github/workflows/ruby.yml

@@ -19,8 +19,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        # ruby-version: ['2.6', '2.7', '3.0']
-        ruby-version: ['2.6']
+        ruby-version: ['2.6', '2.7', '3.0']
         mongodb-version: ['4.4']
         sqlite-version: ['3.0']