Log Message:
Update diffoscope to version 63

This adds a dependency on devel/colordiff.

Changelog for this version:

  * Greatly improve speed for large archives by fixing O(n^2) complexity for
    archive member lookup.
    - There is still O(n^2) complexity for archive member extraction, but this
      is less noticeable for various reasons and would require more complexity
      to fix, so for now is left as a task for the future.
  * Text output: add coloured diff support via colordiff(1).
  * Html-dir output: add +/- buttons to fold sub-diffs (i.e. toggle their
    visibility) as well as the whole diff itself. As with similar features in
    other programs, the effect affects all descendants if you shift-click.

The complete list of changes between version 44 and 63 can be found at
https://anonscm.debian.org/git/reproducible/diffoscope.git/tree/debian/changelog