This update for keybase-client fixes the following issues:

Update to version 6.2.8


  * Update client CA
  * Fix incomplete locking in config file handling.

- Update the Image dependency to address CVE-2023-29408 /
  boo#1213928. This is done via the new update-image-tiff.patch.
- Limit parallel test execution as that seems to cause failing
  builds on OBS that don't occur locally.
- Integrate KBFS packages previously build via own source package
  * Upstream integrated these into the same source.
  * Also includes adding kbfs-related patches
    ensure-mount-dir-exists.patch and
    ensure-service-stop-unmounts-filesystem.patch.
- Upgrade Go version used for compilation to 1.19.
- Use Systemd unit file from upstream source.