chore(deps): update docker.elastic.co/beats/metricbeat docker tag to v8.15.1

Author: renovate[bot]

infrastructure/docker-compose.dependencies.yml

@@ -85,7 +85,7 @@ services:
         - 'traefik.enable=false'
 
   metricbeat:
-    image: docker.elastic.co/beats/metricbeat:8.14.3
+    image: docker.elastic.co/beats/metricbeat:8.15.1
     user: root
     cap_add:
       - SYS_PTRACE