Add nodejs16 to runtime lookup

[danjordan]

What does this PR do?

Add runtime to layer mapping for node 16

Types of changes

• [ ] Bug fix
• [x] New feature
• [ ] Breaking change
• [ ] 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

[DarcyRaynerDD]

Hi Dan, thanks for this PR! We decided to roll our own pr #66, since there were a few other things we had to do for the release.

[danjordan]

Hey! Cheers for the response.

Sorry for using Github as support, but do you know when this will be available to use in AWS?

Thanks