Support Lambda runtime lookup for provided.al2023 (AWS recommended for Go functions)

[benjamin-scc]

Expected Behavior

Lambda layer to be added and output in CDK synthesized template under Layers for type AWS::Lambda::Function

Actual Behavior

Missing Lambda layer when Lambda runtime is provided.al2023

Steps to Reproduce the Problem

1. Using the latest version: "datadog-cdk-constructs-v2": "1.14.1" (NOTE: Looks to have been an issue since version >= 1.7.4)
2. With CDK code

const lambda = new lambda.Function(this, id, {
  runtime: aws_lambda.Runtime.PROVIDED_AL2023,
  architecture: aws_lambda.Architecture.ARM_64,
  ...
})

const datadog = new Datadog(this, 'Datadog', {
  ...
})

datadog.addLambdaFunctions([lambda])

1. cdk synth
2. Inspect synthesized output template file (cdk.out/*.template.json) to find the Lambda is missing layer

Specifications

Add "provided.al2023": RuntimeType.CUSTOM to runtimeLookup in constants.ts

See - https://github.com/DataDog/datadog-cdk-constructs/blob/main/src/constants.ts#L51-L72

References

• Lambda runtimes - https://docs.aws.amazon.com/lambda/latest/dg/lambda-runtimes.html
• Using AL2023 on AWS - https://docs.aws.amazon.com/linux/al2023/ug/aws.html
• Migrating AWS Lambda functions from the Go1.x runtime to the custom runtime on Amazon Linux 2 - https://aws.amazon.com/blogs/compute/migrating-aws-lambda-functions-from-the-go1-x-runtime-to-the-custom-runtime-on-amazon-linux-2/