Fix libre-gateway health check url

Author: tomhollingworth

Standalone/docker-compose.yml

@@ -200,7 +200,7 @@ services:
       interval: 5s
       timeout: 3s
       retries: 5
-      test: ["CMD", "curl", "-f", "http://libre-gateway:4000"]
+      test: ["CMD", "curl", "-f", "http://libre-gateway:4000/health"]
   grafana:
     image: grafana/grafana:latest
     container_name: grafana
@@ -244,4 +244,4 @@ services:
         condition: service_healthy
       influxdb:
         condition: service_healthy
-    container_name: libre-edge-agent
+    container_name: libre-edge-agent