d/copyright: update Files-Excluded

Author: Lucas Kanashiro

debian/copyright

@@ -1,7 +1,7 @@
 Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
 Upstream-Name: ruby
 Source: https://ftp.ruby-lang.org/pub/ruby/
-Files-Excluded: gems/*-* ext/fiddle/libffi-*
+Files-Excluded: gems/*-*
 
 Files: *
 Copyright: Yukihiro Matsumoto <[email protected]> and others