Adapt copyright years.

* debbugs-gnu.el (debbugs-gnu-default-packages): Extend list of packages.
(debbugs-gnu-get-bugs): Support 'bugs query.
(debbugs-gnu-usertags): Simplify implementation.
(debbugs-gnu-bugs): New defun.
* debbugs-gnu.el : Require wid-edit.el.