Fix git url for goxxerrors project

# vim: filetype=yaml sw=2

version: '[% c("abbrev") %]'

git_url: https://golang.org/x/xerrors

git_url: https://go.googlesource.com/xerrors

git_hash: 9bdfabe68543c54f90421aeb9a60ef8061b5b544

filename: '[% project %]-[% c("version") %]-[% c("var/osname") %]-[% c("var/build_id") %].tar.gz'