Use latest truffleruby version

* Older versions are not supported.

Author: eregon

.github/workflows/test.yaml

@@ -88,7 +88,7 @@ jobs:
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: truffleruby-22.2.0
+          ruby-version: truffleruby
           bundler-cache: true
       - name: Cache local temporary directory
         uses: actions/cache@v3