Added Ruby 3.4 to the CI (closes #22).

Author: postmodern

.github/workflows/ruby.yml

@@ -13,6 +13,7 @@ jobs:
           - '3.1'
           - '3.2'
           - '3.3'
+          - '3.4'
           - jruby
           - truffleruby
     name: Ruby ${{ matrix.ruby }}