Copyright for android-sdk-helper source package in Bionic

Format: http://www.debian.org/doc/packaging-manuals/copyright-format/1.0

Files: *
Copyright: 2017, Kai-Chung Yan (殷啟聰)
License: Apache-2.0
 On Debian systems, the full text of the Apache-2.0 license
 can be found in the file '/usr/share/common-licenses/Apache-2.0'