[glom] appdata: Use <image> and <caption> tags.

[Murray Cumming <murrayc src gnome org>]

commit 2e39006c47b5650a85b5c8211a56241c3674e17b
Author: Murray Cumming <murrayc murrayc com>
Date:   Sat Nov 28 13:17:49 2015 +0100

    appdata: Use <image> and <caption> tags.
    
    This also seems to be the new way to do things.

 glom.appdata.xml.in |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/glom.appdata.xml.in b/glom.appdata.xml.in
index d76dc38..3c339cd 100644
--- a/glom.appdata.xml.in
+++ b/glom.appdata.xml.in
@@ -15,7 +15,10 @@
     </p>
   </description>
   <screenshots>
-    <screenshot type="default">http://www.glom.org/wiki/images/7/7b/Small_glom_data_details.png</screenshot>
+    <screenshot type="default">
+      <image>http://www.glom.org/wiki/images/7/7b/Small_glom_data_details.png</image>
+      <caption>The details view showing the whole record</caption>
+      </screenshot>
   </screenshots>
   <url type="homepage">http://www.glom.org/</url>
   <updatecontact>murrayc_at_murrayc.com</updatecontact>