chore: pin testbench version (#1757)

Author: ddelgrosso1

conformance-test/test-bench-util.ts

@@ -21,7 +21,7 @@ const PORT = new URL(HOST).port;
 const CONTAINER_NAME = 'storage-testbench';
 const DEFAULT_IMAGE_NAME =
  'gcr.io/cloud-devrel-public-resources/storage-testbench';
-const DEFAULT_IMAGE_TAG = 'latest';
+const DEFAULT_IMAGE_TAG = 'v0.10.0';
 const DOCKER_IMAGE = `${DEFAULT_IMAGE_NAME}:${DEFAULT_IMAGE_TAG}`;
 const PULL_CMD = `docker pull ${DOCKER_IMAGE}`;
 const RUN_CMD = `docker run --rm -d -p ${PORT}:${PORT} --name ${CONTAINER_NAME} ${DOCKER_IMAGE} && sleep 1`;