Merge pull request etcd-io#20600 from ivanvc/pin-antithesis-to-v0.9

dependency: lock antithesis-trigger-action to v0.9

Author: serathius

.github/workflows/antithesis-test.yml

@@ -82,7 +82,7 @@ jobs:
           docker push $IMAGE
 
       - name: Run Antithesis Tests
-        uses: antithesishq/antithesis-trigger-action@6c0a27302c0a3cd97d87d40bd6704e673abed4bb # main commit on Mar 13, 2025
+        uses: antithesishq/antithesis-trigger-action@6c0a27302c0a3cd97d87d40bd6704e673abed4bb # v0.9
         with:
           notebook_name: etcd
           tenant: linuxfoundation