Add a workflow to ensure the gem builds fine on TruffleRuby

.github/workflows/truffleruby.yml

@@ -0,0 +1,24 @@
+name: TruffleRuby
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  truffleruby:
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: truffleruby-head
+        bundler-cache: true
+    - name: Test installing the gem on TruffleRuby
+      run: |
+        bundle exec rake compile
+        bundle exec rake build
+        gem install pkg/debug-*.gem