chore(deps): update zabbix/zabbix-agent:alpine-6.0-latest docker digest to 4686ff4 (#2202)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| zabbix/zabbix-agent | digest | `9eab77e` → `4686ff4` |

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devenv/zabbix60/docker-compose.yml

@@ -73,7 +73,7 @@ services:
       POSTGRES_PASSWORD: zabbix
 
   zabbix-agent:
-    image: zabbix/zabbix-agent:alpine-6.0-latest@sha256:9eab77e4f23e68746f935ab71f3c828a6bfc73b2e2783c5453d61a24f996bb6b
+    image: zabbix/zabbix-agent:alpine-6.0-latest@sha256:4686ff4dd5c7e3ea43e9653e35019039e567c544495f55fcb949c2cdd0a6cf50
     environment:
       ZBX_SERVER_HOST: zabbix-server
       ZBX_SERVER_PORT: 10051