Add support for eu-west-3

[motatoes]

eu-west-3 is a valid region but is not supported by fargate cli.

fargate task describe --region eu-west-3

[!] Invalid region: eu-west-3 [valid regions: us-east-1, us-east-2, us-west-1, us-west-2, ca-central-1, eu-west-1, eu-west-2, eu-central-1, ap-southeast-1, ap-southeast-2, ap-northeast-1, ap-northheast-2, ap-south-1]

[rafaelsiqueira]

Same here with sa-east-1.

[motatoes]

@rafaelsiqueria I ended up fixing this in a fork since I don't think this repository is maintained anymore https://github.com/diggerhq/fargate/pull/1/files