Enable CloudWatch metrics for Athena workgroups

[timoguin]

CloudWatch metrics for the Matano Athena workgroups are not enabled. Let's turn them on.

References

• https://docs.aws.amazon.com/athena/latest/ug/athena-cloudwatch-metrics-enable.html
• https://docs.aws.amazon.com/athena/latest/ug/query-metrics-viewing.html