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

Author: renovate[bot]

examples/example-exemplars-tail-sampling/docker-compose.yaml

@@ -59,7 +59,7 @@ services:
     command:
       - --config.file=/config.yaml
   grafana:
-    image: grafana/grafana:12.3.0@sha256:70d9599b186ce287be0d2c5ba9a78acb2e86c1a68c9c41449454d0fc3eeb84e8
+    image: grafana/grafana:12.3.1@sha256:adaf2d6b44c7e2b711b931b98be153778d313806582a24eab21178804fac2976
     network_mode: host
     ports:
       - "3000:3000"

examples/example-native-histogram/docker-compose.yaml

@@ -18,7 +18,7 @@ services:
       - --enable-feature=native-histograms
       - --config.file=/prometheus.yml
   grafana:
-    image: grafana/grafana:12.3.0@sha256:70d9599b186ce287be0d2c5ba9a78acb2e86c1a68c9c41449454d0fc3eeb84e8
+    image: grafana/grafana:12.3.1@sha256:adaf2d6b44c7e2b711b931b98be153778d313806582a24eab21178804fac2976
     network_mode: host
     volumes:
       - ./docker-compose/grafana-datasources.yaml:/etc/grafana/provisioning/datasources/grafana-datasources.yaml