chore(deps): update grafana/grafana docker tag to v12.3.1

Author: renovate[bot]

src/Pi4/docker-compose.yml

@@ -100,7 +100,7 @@ services:
       - "traefik.http.routers.prometheus.middlewares=auth@file"
 
   grafana:
-    image: grafana/grafana:12.3.0
+    image: grafana/grafana:12.3.1
     container_name: grafana
     restart: always
     environment: