Migrate to aws-xray-sdk-go/v2

[krzysiek1507]

What does this PR do?

Migrate to aws-xray-sdk-go/v2 so we don't pull aws-sdk-go v1 anymore.

Motivation

aws-xray-sdk-go v1 uses aws-sdk-go v1 which is heave and also not used in the repo.

Testing Guidelines

Additional Notes

Types of changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

Checklist

• This PR's description is comprehensive
• This PR contains breaking changes that are documented in the description
• This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• This PR impacts documentation, and it has been updated (or a ticket has been logged)
• This PR's changes are covered by the automated tests
• This PR collects user input/sensitive content into Datadog

[krzysiek1507]

Hey @purple4reina! Would you be able to take a look at this PR? Thanks!

[krzysiek1507]

Any idea why ENV variables would be empty for the integration test?

No AWS credentials were found in the environment.

[purple4reina]

Hey @krzysiek1507, thanks a ton for the contribution. I've reopened your branch under a new PR at #194 so that we can run the integration tests.

[krzysiek1507]

@purple4reina thank you very much! Once the other PR is merged, I would really appreciate a new release

[purple4reina]

https://github.com/DataDog/datadog-lambda-go/releases/tag/v1.22.0 has been released with these changes 🎉