ops traefik placeholder: add healthcheck

Author: YuryHrytsuk

services/simcore/docker-compose.yml.j2

@@ -871,6 +871,12 @@ services:
         - traefik.http.services.${SWARM_STACK_NAME}_simcore_api_fallback.loadbalancer.healthcheck.path=/some/invalid/path/to/generate/a/503
         - traefik.http.services.${SWARM_STACK_NAME}_simcore_api_fallback.loadbalancer.healthcheck.interval=10s
         - traefik.http.services.${SWARM_STACK_NAME}_simcore_api_fallback.loadbalancer.healthcheck.timeout=1ms
+    healthcheck:
+      test: command -v sleep
+      interval: 10s
+      timeout: 1s
+      start_period: 1s
+      retries: 1
 
   traefik-configuration-placeholder: # simcore traefik with `io.simcore.zone=${TRAEFIK_SIMCORE_ZONE}` label
     image: busybox:1.35.0