Appastream: Correcting license

Got a hint from the flatpak people on IRC and connected the license IDs with and "AND". Works perfectly fine with Gnome's software center.

Signed-off-by: Thomas Karl Pietrowski <thopiekar@gmail.com>

deploy/org.mavlink.qgroundcontrol.metainfo.xml

@@ -6,8 +6,8 @@
   <summary>UAS ground control station</summary>
   <developer_name>Dronecode Project, Inc.</developer_name>
   
-  <metadata_license>MIT</metadata_license>
-  <project_license>GPL-3.0</project_license>
+  <metadata_license>GPL-3.0 AND Apache-2.0</metadata_license>
+  <project_license>GPL-3.0 AND Apache-2.0</project_license>
   
   <recommends>
     <control>pointing</control>