Ability to attach a custom iAM policy to lambdas

[boosh]

Describe the Feature

Custom lambda@edge permissions

Expected Behavior

I wanted to provide a custom IAM policy but it doesn't seem possible since it's only attached at creation time I think.

Use Case

Trying to permit access to other services for use within the lambda (e.g. S3), but can't.

Describe Ideal Solution

The module would permit passing in a custom IAM role/policy to be attached.

Alternatives Considered

Not using the module

Additional Context

No response