ci(release): set podman canary handshake secret

Author: drew

.github/workflows/release-canary.yml

@@ -248,6 +248,7 @@ jobs:
             OPENSHELL_DB_URL="sqlite:${HOME}/.local/state/openshell/gateway/openshell.db" \
             OPENSHELL_PODMAN_SOCKET=/run/podman/podman.sock \
             OPENSHELL_GRPC_ENDPOINT=http://host.containers.internal:17670 \
+            OPENSHELL_SSH_HANDSHAKE_SECRET=release-canary-secret \
             OPENSHELL_SUPERVISOR_IMAGE=ghcr.io/nvidia/openshell/supervisor:latest \
             openshell-gateway > /tmp/openshell-gateway.log 2>&1 &