fix branch name of site repo

update-gluon.sh

@@ -5,6 +5,7 @@ set -eu
 set -o pipefail
 
 gluon_major="v2019.1"
+site_branch="v1.8"
 
 gluon_fork_git_url="ssh://git@gitlab.freifunk-stuttgart.de:22220/firmware/gluon.git"
 gluon_upstream_git_url="https://github.com/freifunk-gluon/gluon.git"
@@ -40,7 +41,7 @@ cd ..
 git clone --recurse "$site_git_url"
 
 cd site-ffs
-git checkout "gluon-$gluon_major"
+git checkout "$site_branch"
 
 git submodule sync
 git submodule update