Update python-watermark to version 2.3.0 / rev 6 via SR 956264
    
    https://build.opensuse.org/request/show/956264
    by user bnavigator + dimstar_suse
    - specfile:
      * update copyright year
      * skip python 3.6
    - update to version 2.3.0:
      * Added the following arguments: --github_username - for prints
        author github username, --email - for prints author email,
        --website - for prints author or project website. (#82, via
        contribution by joschkazj)
      * Added a --conda option to print the name of the current conda
        environment. (#79, via contribution by Alexander Krasnikov)
      * It is now possible to inject globals when used outside IPython
        (#80, via contribution by Hugo Lapré). For example, version
        numbers of imported packages can now be obtained as follows:
            import numpy
            import watermark.watermark as watermark
            watermark(iversions=True, globals_=globals())
    - changes from version 2.2.0:
      * Refactori