Copyright for rust-fs-at source package in Huanghe V3.0

Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
Upstream-Name: fs_at
Upstream-Contact: Robert Collins 
Source: https://github.com/rbtcollins/fs_at.git

Files: *
Copyright: 2022-2023 Robert Collins 
License: Apache-2.0

Files: debian/*
Copyright:
 2023 Debian Rust Maintainers 
 2023 Zixing Liu 
License: Apache-2.0

License: Apache-2.0
 Debian systems provide the Apache 2.0 license in
 /usr/share/common-licenses/Apache-2.0