Remove truffleruby head from CI tests (#1759)

Author: jar-stripe

.github/workflows/ci.yml

@@ -47,7 +47,7 @@ jobs:
     strategy:
       matrix:
         # following https://docs.stripe.com/sdks/versioning?lang=ruby#stripe-sdk-language-version-support-policy
-        ruby-version: [2.6, 2.7, '3.0', 3.1, 3.2, 3.3, 3.4, jruby-9.4.0.0, truffleruby-head]
+        ruby-version: [2.6, 2.7, '3.0', 3.1, 3.2, 3.3, 3.4, jruby-9.4.0.0, truffleruby-25.0.0]
     steps:
     - uses: extractions/setup-just@v2
     - uses: actions/checkout@v3