[Enhancement] - Ability to specify a specific bucket prefix to upload code to

[JustinH11235]

As far as I can tell from the source, it seems like the user has no input to control the prefix of the uploaded code. The s3.upload_fileobj() is used but the key that would normally contain the prefix you wanted is hardcoded as shown in the linked line. I suggest that either the user can specify another command line option such as --prefix and give a prefix that way, or to add the functionality to --bucket, where I can write my-bucket-name/prefix and it will parse out the prefix, putting it as the start of the key parameter.

https://github.com/aws-samples/sagemaker-studio-image-build-cli/blob/master/sagemaker_studio_image_build/builder.py#L30

[ecrows]

+1 This is a small but important feature for situations where the IAM role only has PutObject access to specific prefixes in a bucket. I can work on a PR for this if that would be helpful.