feat: Add support for Node 20

[duncanista]

What does this PR do?

Adds support for Node 20 as it's available for AWS Lambda.

Motivation

It's widely available, and the latest layer (v100) has already been released with support for it.

Also #110

Testing Guidelines

• [x] Unit tests

Additional Notes

Types of changes

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

Check all that apply

• [ ] 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