Remove triple-dash from rendered yaml

[asenci]

Tripple-dash ("---") causes the following section of the configuration to be ignored by the Datadog agent

i.e:

    options:               # Optional
        replication: 1
        galera_cluster: 0
        extra_status_metrics: false
        extra_innodb_metrics: false
        extra_performance_metrics: false
        schema_size_metrics: false
        disable_innodb_metrics: false



---
logs:
- type: file
  path: "/var/lib/mysql/mysqld.log"
  service: mysql
  source: mysql

[albertvaka]

Good catch!