bump to ruby 3

Author: kenyonj

Diff for: .github/workflows/ci.yml

@@ -11,10 +11,10 @@ jobs:
     strategy:
       matrix:
         ruby:
-          - "2.4"
-          - "2.5"
-          - "2.6"
-          - "2.7"
+          - "3.0"
+          - "3.1"
+          - "3.2"
+          - "3.3"
       fail-fast: false
 
     steps: