Merge pull request #266 from toshimaru/ruby-3.3

CI against Ruby v3.3

Author: zerowidth

.github/workflows/ci.yml

@@ -24,6 +24,7 @@ jobs:
           - "3.0"
           - "3.1"
           - "3.2"
+          - "3.3"
     steps:
       - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1