Drop the Gluon version reference from the site configuration used for
the CI builds.

These version indicators were most likely just copied from the example
site in the docs, where the version information makes sense. However,
the CI site is always built for a specific Gluon version and therefor
commit.

This avoids editing the version for each release.

Signed-off-by: David Bauer <mail@david-bauer.net>
(cherry picked from commit 1ec9943539638249a3ee72646b4b6dc605a19306)