Update Ruby 4 to preview3 in CI matrix

Author: cllns

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
       fail-fast: false
       matrix:
         ruby:
-          - "4.0.0-preview2"
+          - "4.0.0-preview3"
           - "3.4"
           - "3.3"
           - "3.2"