devel/gcli: update to 2.6.0
Upstream has now added support for liblowdown-2.4.0, so remove our
site patch.
Changelog: https://lists.sr.ht/~herrhotzenplotz/gcli-announce/%3C2DKRRDGOKZUVX.1ZO3F4M3P32HD@triton.lab.herrhotzenplotz.de%3E
(cherry picked from commit 79193349858083ec16d96c50da6ec3a821b9d365)