Fix invitations traefik configuration

traefik http service name should be `invitations` (not `webserver`).
This is a typo (after copy pasting)

Related PR(s):
* Bug was introduced in ITISFoundation#950

Author: YuryHrytsuk

services/simcore/docker-compose.yml.j2

@@ -190,9 +190,9 @@ services:
         - traefik.http.routers.${SWARM_STACK_NAME}_invitations.rule=(${DEPLOYMENT_FQDNS_CAPTURE_INVITATIONS})
         - traefik.http.routers.${SWARM_STACK_NAME}_invitations.entrypoints=http
         - traefik.http.services.${SWARM_STACK_NAME}_invitations.loadbalancer.server.port=8000
-        - traefik.http.services.${SWARM_STACK_NAME}_webserver.loadbalancer.healthcheck.path=/
-        - traefik.http.services.${SWARM_STACK_NAME}_webserver.loadbalancer.healthcheck.interval=2000ms
-        - traefik.http.services.${SWARM_STACK_NAME}_webserver.loadbalancer.healthcheck.timeout=1000ms
+        - traefik.http.services.${SWARM_STACK_NAME}_invitations.loadbalancer.healthcheck.path=/
+        - traefik.http.services.${SWARM_STACK_NAME}_invitations.loadbalancer.healthcheck.interval=2000ms
+        - traefik.http.services.${SWARM_STACK_NAME}_invitations.loadbalancer.healthcheck.timeout=1000ms
         - traefik.http.routers.${SWARM_STACK_NAME}_invitations_swagger.rule=(${DEPLOYMENT_FQDNS_CAPTURE_INVITATIONS}) && PathPrefix(`/dev/doc`)
         - traefik.http.routers.${SWARM_STACK_NAME}_invitations_swagger.entrypoints=http
         - traefik.http.middlewares.${SWARM_STACK_NAME_NO_HYPHEN}_invitations_swagger_auth.basicauth.users=${TRAEFIK_USER}:${TRAEFIK_PASSWORD}