archbuild: Install appstream-generator for arojas

Signed-off-by: Florian Pritz <bluewind@xinu.at>

roles/archbuild/tasks/main.yml

 ---
 
+- name: install additional buildserver support packages
+  pacman: name={{item}} state=present
+  with_items:
+    - appstream-generator
+
 - name: install archbuild
   pacman: name=systemd-swap,devtools,zsh,git,subversion,mercurial,bzr,xdelta3,ruby,tig,colordiff state=present