chore(deps): pin dependencies

Signed-off-by: renovate-sh-app[bot] <219655108+renovate-sh-app[bot]@users.noreply.github.com>

Author: renovate-sh-app[bot]

docker-compose.yml

@@ -1,11 +1,11 @@
 services:
   ngrok:
-    image: ngrok/ngrok:latest
+    image: ngrok/ngrok:latest@sha256:50234a734982cdb63d762c2f9983546257f414aa2535917d66ba9433da74f525
     command: http --url=${NGROK_SUBDOMAIN} grafana:3000
     environment:
       NGROK_AUTHTOKEN: ${NGROK_AUTHTOKEN}
   grafana:
-    image: grafana/grafana:main
+    image: grafana/grafana:main@sha256:3ca2bbe08dfc62c5bc71cd8a604fabf511036561018ba7fa1cca6dee286982a6
     environment:
       - GF_FEATURE_TOGGLES_ENABLE=provisioning,kubernetesDashboards
       - GF_RENDERING_SERVER_URL=http://renderer:8081/render
@@ -21,7 +21,7 @@ services:
       - ngrok
     restart: unless-stopped
   renderer:
-    image: grafana/grafana-image-renderer:latest
+    image: grafana/grafana-image-renderer:latest@sha256:c73922a1027e6f0411b228d8c32baad06684483a42dbe70f17f324eaefd0ae7d
     ports:
       - 8081