VSCode Debug SourceMap Location

### Describe your idea/feature/enhancement

I'm not sure if this already exists, but I can't see it readily documented. I'd like to be able to debug locally in VSCode using a launch configuration, and using the new typescript beta-features. While esbuild is emitting sourcemaps, it's dropping those into the .aws-sam/build/** folders and therefore the debug cannot locate them relative to the source code.

Is there a way for me to specify an alternative location for the sourcemaps to be emitted, or can I tell VSCode where to look? I've tried to add resolveSourceMapLocations but it doesn't recognise the option under the configuration type of aws-sam.

Thanks!