Add Ruby 3.4 to CI.

Author: ppostma

.github/workflows/test.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