AWS EU-South-1 Unsupported Region

#### Overview of the Issue

eu-south-1 region is not support

#### Reproduction Steps

```
..................
Initializing template: share/packer/amazon/linux
13:03:27 [Pipeline] sh
13:03:28 + PACKER_LOG=0
13:03:28 + packer init share/packer/amazon/linux
13:03:45 Installed plugin github.com/hashicorp/amazon v1.0.8 in "/home/jenkins.internal.preprod/workspace/MCO/Images/SLES12-Image/.packer.d/github.com/hashicorp/amazon/packer-plugin-amazon_v1.0.8_x5.0_linux_amd64"
13:03:45 [Pipeline] }
13:03:45 [Pipeline] // dir
13:03:45 [Pipeline] sh
13:03:46 + packer build -var-file=packer/components/common-sles12.pkrvars.hcl -var-file=component.json -var-file=ami_regions.json -var ansible_username=ec2-user -var spot_price=0 -var instance_type=t2.micro packer-templates/share/packer/amazon/linux/
13:04:03 amazon-ebs.linux: output will be in this color.
13:04:03
13:04:03 Build 'amazon-ebs.linux' errored after 70 milliseconds 607 microseconds: error validating regions: Invalid region(s): [eu-south-1], available regions: [eu-north-1 ap-south-1 eu-west-3 eu-west-2 eu-west-1 ap-northeast-3 ap-northeast-2 ap-northeast-1 sa-east-1 ca-central-1 ap-southeast-1 ap-southeast-2 eu-central-1 us-east-1 us-east-2 us-west-1 us-west-2]
13:04:03
13:04:03 ==> Wait completed after 70 milliseconds 665 microseconds
13:04:03
13:04:03 ==> Some builds didn't complete successfully and had errors:
13:04:03 --> amazon-ebs.linux: error validating regions: Invalid region(s): [eu-south-1], available regions: [eu-north-1 ap-south-1 eu-west-3 eu-west-2 eu-west-1 ap-northeast-3 ap-northeast-2 ap-northeast-1 sa-east-1 ca-central-1 ap-southeast-1 ap-southeast-2 eu-central-1 us-east-1 us-east-2 us-west-1 us-west-2]
```

### Plugin and Packer version

packer: `1.7.10`
aws plugin: `packer-plugin-amazon_v1.0.8_x5.0_linux_amd64`