Small fix: Remove hardcoded env-var TRAEFIK_SIMCORE_ZONE

Author: mrnicegyu11

services/traefik/template.env

@@ -94,7 +94,7 @@ TRAEFIK_ENTRYPOINTS_REDIS_ADDRESS=${REDIS_EXTERNAL_PORT}
 # Providers
 TRAEFIK_PROVIDERS_SWARM_ENDPOINT=unix:///var/run/docker.sock
 TRAEFIK_PROVIDERS_SWARM_EXPOSEDBYDEFAULT=false
-TRAEFIK_PROVIDERS_SWARM_CONSTRAINTS='!Label(`io.simcore.zone`,`master_internal_simcore_stack`)'
+TRAEFIK_PROVIDERS_SWARM_CONSTRAINTS='!Label(`io.simcore.zone`,`'${TRAEFIK_SIMCORE_ZONE}'`)'
 TRAEFIK_PROVIDERS_FILE_DIRECTORY=/etc/traefik/
 TRAEFIK_PROVIDERS_FILE_WATCH=true