Update b4 to version 0.13.0 / rev 40 via SR 1146990
    
    https://build.opensuse.org/request/show/1146990
    by user jirislaby + anag+factory
    - update to 0.13.0:
      * `b4 am` now has a `--single-message` flag that lets you process a
        single message and ignore any other parts of a thread; this is
        useful when there is a patch series sent as attachments to a single
        message
      * `--apply-cover-trailers` is now the default behaviour
      * when patchwork integration is configured, `b4 am` will attempt to
        retrieve the CI status of patches
      * `b4 prep --show-info` can do a lot more now, including showing
        information about branches that aren't currently checked out
      * `b4 prep` gained a --cleanup option to properly archive and remove
        old b4*prep-managed branches
      * `b4 send` has a `--preview-to` option that lets you send a
        pre*review of your series to your colleagues, mentors, or bosses
      * various fixes and impr