Copy to non-existing S3 folder path creates a file with "/" instead of file name in that folder

[quantori-pokidovea]

Steps to reproduce:

# take an existing file
src = S3Path("s3://my-bucket/file.txt")
# and copy it into non-existent folder
dst = S3Path("s3://my-bucket/destination/")

src.copy(dst)

Current behavior

Creates a file with name / inside the folder s3://my-bucket/destination/

Expected behavior

The file s3://my-bucket/destination/file.txt is created