Test on ruby 3.4 preview

Author: dduugg

.github/workflows/ruby.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['3.0', '3.1', '3.2', '3.3']
+        ruby-version: ['3.0', '3.1', '3.2', '3.3', '3.4']
     steps:
       - uses: actions/checkout@v4
       - name: Set up Ruby