cadvisor: add /dev/kmsg/ and update to v0.47.2

cadvisor/init.sls

 {% set docker = salt['pillar.get']('docker', {}) %}
 {% set volume = docker.volume_root | default('/srv/docker') ~ '/cadvisor' %}
-{% set image = 'gcr.io/cadvisor/cadvisor:v0.37.0' %}
+{% set image = 'gcr.io/cadvisor/cadvisor:v0.47.2' %}
 {% set cadvisor = salt['pillar.get']('cadvisor', {}) %}
 {% set metrics = cadvisor.get('metrics', {}) %}
 {% set port = '9999' %}
@@ -33,6 +33,7 @@ docker-container-cadvisor:
       - /sys:/sys:ro
       - /var/lib/docker/:/var/lib/docker:ro
       - /dev/disk/:/dev/disk:ro
+      - /dev/kmsg/:/dev/kmsg:ro
     - require:
       - docker_image: docker-image-{{ image }}
     - watch: