feat(ec2): add c8gn instance class

[phuhung273]

Issue # (if applicable)

None

Reason for this change

https://aws.amazon.com/about-aws/whats-new/2025/06/amazon-ec2-c8gn-instance/

Description of changes

EC2 add c8gn instance class

Describe any new or updated permissions being added

Description of how you validated changes

$ aws ec2 describe-instance-types | grep -e c8gn
            "InstanceType": "c8gn.4xlarge",
            "InstanceType": "c8gn.16xlarge",
            "InstanceType": "c8gn.8xlarge",
            "InstanceType": "c8gn.12xlarge",
            "InstanceType": "c8gn.xlarge",
            "InstanceType": "c8gn.48xlarge",
            "InstanceType": "c8gn.2xlarge",
            "InstanceType": "c8gn.metal-24xl",
            "InstanceType": "c8gn.large",
            "InstanceType": "c8gn.medium",
            "InstanceType": "c8gn.24xlarge",
            "InstanceType": "c8gn.metal-48xl",

Checklist

• My code adheres to the CONTRIBUTING GUIDE and DESIGN GUIDELINES

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

[aws-cdk-automation]

(This review is outdated)

[phuhung273]

Exemption Request: change can be verified with CLI

✅ Updated pull request passes all PRLinter validations. Dismissing previous PRLinter review.

[mergify]

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Thank you for contributing! Your pull request will be updated from main and then merged automatically (do not update manually, and be sure to allow changes to be pushed to your fork).

[aws-cdk-automation]

AWS CodeBuild CI Report

• CodeBuild project: AutoBuildv2Project1C6BFA3F-wQm2hXv2jqQv
• Commit ID: 64b5b81
• Result: SUCCEEDED
• Build Logs (available for 30 days)

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[mergify]

Thank you for contributing! Your pull request will be updated from main and then merged automatically (do not update manually, and be sure to allow changes to be pushed to your fork).

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