[gnome-color-manager] Add a missing tag to the AppData file

[Richard Hughes <rhughes src gnome org>]

commit 95b19274c6adb58dda6f3f70df2745118a90a301
Author: Richard Hughes <richard hughsie com>
Date:   Mon Jan 25 13:35:39 2016 +0000

    Add a missing tag to the AppData file

 data/appdata/gcm-viewer.appdata.xml.in |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/data/appdata/gcm-viewer.appdata.xml.in b/data/appdata/gcm-viewer.appdata.xml.in
index 8a00b3f..ad48aae 100644
--- a/data/appdata/gcm-viewer.appdata.xml.in
+++ b/data/appdata/gcm-viewer.appdata.xml.in
@@ -80,4 +80,5 @@
   </kudos>
   <url type="homepage">https://projects.gnome.org/gnome-color-manager/</url>
   <updatecontact>richard_at_hughsie.com</updatecontact>
+  <project_group>GNOME</project_group>
 </application>