AWS region check recommends setting `default.region` but checks `region`

[acdha]

My environment had $AWS_DEFAULT_REGION and the AWS CLI default.region key set but did not have the separate region key set. This meant that the error message is misleading:

Pre-flight check failed: Missing AWS region. Use the `aws configure set default.region` command or set the "AWS_REGION" environment variable.

The configure command, of course, does nothing because aws configure get default.region would already have displayed the expected value. The error was easily avoided by running aws configure set region $AWS_DEFAULT_REGION but it feels like this should recommend setting the same value it checks. There's also a thought that if you passed it a full ARN for the task ID the embedded region should be used since many people use more than a single region.