Copyright for rust-encoding-index-korean source package in Focal

Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
Upstream-Name: encoding-index-korean
Upstream-Contact: Kang Seonghoon 

Files: *
Copyright: 2014-2015 Kang Seonghoon 
License: CC0-1.0

Files: debian/*
Copyright:
 2018 Debian Rust Maintainers 
 2018 Wolfgang Silbermayr 
License: CC0-1.0

License: CC0-1.0
 Debian systems provide the CC0 1.0 Universal License in
 /usr/share/common-licenses/CC0-1.0