chore: replace aws-sdk-go v1 with v2

[byF]

Summary

Migrates Copilot’s AWS integration from aws-sdk-go to aws-sdk-go-v2.

• Replaces v1 AWS SDK dependencies with SDK v2 service modules and removes remaining v1 imports.
• Updates shared AWS session/config handling to use SDK v2 config, credentials, retry, timeout, assume-role, and User-Agent behavior.
• Migrates AWS service wrappers, CLI callers, deploy/describe/manifest paths, tests, and generated mocks to SDK v2 request/response/types.

Other work:

• Disables automatic binary size CI for PRs and makes the license script portable across environments.

Verification

Existing unit and integration test coverage was updated for the SDK v2 interfaces; no additional tests were run while drafting this description.

Disclaimer

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the Apache 2.0 License.

[github-actions]

🍕 Here are the new binary sizes!

Name	New size (kiB)	size (kiB)	Delta (%)
macOS (amd)	56312	53336	😭 +5.58
macOS (arm)	53472	50776	😭 +5.31
linux (amd)	54652	51760	😭 +5.59
linux (arm)	51460	48904	😭 +5.23
windows (amd)	51004	48308	😭 +5.58