Region should not default to us-east-1

[mildebrandt]

When running in an ECS container, I would expect the package to inherit the AWS settings from the container instead of defaulting to us-east-1. I would rather not specify the region since the container knows where it is.

[hectcastro]

Hey @mildebrandt, I think the reason why we require this setting is because SES is not available in all regions. We have application instances running in ECS currently that use a different SES region endpoint than the region they operate in.

[mildebrandt]

Hi @hectcastro!

So, what I did was stand-up an ECS container in us-west-2 without any settings pointing to a specific region, and it attempted to send e-mail through us-east-1. If SES is not available in the region my container is in, then I would expect the API call to fail. Making the default us-east-1 will fail for anyone using other regions since their e-mail addresses aren't verified in us-east-1.

This issue is about changing the default from us-east-1 to the region of the instance. I think that would be a more logical default.