windows paths contain backwards slashes

[johanvdw]

When I try to upload a file from a windows build of this plugin (for windows 2019) to minio, I see that the backwards slashes from the path become part of the filename.

time="2021-11-26T08:57:19+01:00" level=info msg="Attempting to upload" bucket=conda endpoint="https://minio.xxx.net" region=us-east-1
--
5 | time="2021-11-26T08:57:19+01:00" level=info msg="Uploading file" bucket=conda name=conda_build/win-64/cn_ws-4.2.0-0.tar.bz2 target="/\\win-64\\cn_ws-4.2.0-0.tar.bz2"

Note I did compile the exe on linux, if that could be the issue, I can try rebuilding it on windows.

I saw the same behaviour when using the s3-sync plugin.