Update diffoscope to version 233 / rev 39 via SR 1060127
    
    https://build.opensuse.org/request/show/1060127
    by user dirkmueller + dimstar_suse
    - update to 233:
      * Split packaging metadata into an extras_require.json file instead of using
        the pep517 and the pip modules directly. This was causing build failures if
        not using a virtualenv and/or building without internet access.
      * Add an external tool reference for GNU Guix (lzip).
      * Drop an external tool reference for GNU Guix (pedump).
      * Split inline Python code in shell script to generate test dependencies to a
        separate Python script.
      * No need for "from __future__ import print_function" import in setup.py
        anymore.
      * Comment and tidy the new extras_require.json handling.