AppData: Remove the beta entry from releases

AppStream tries to put the beta on top of release (because of -beta1 in the name); meanwhile beta is not supposed to be in use now in the first place.

Author: KitsuneRal

linux/com.github.quaternion.appdata.xml

@@ -37,7 +37,6 @@
 
   <releases>
     <release version="0.0.9.4" date="2019-04-29" />
-    <release version="0.0.9.4-beta1" date="2019-03-03" type="development" />
     <release version="0.0.9.3" date="2018-10-21" />
     <release version="0.0.9.2" date="2018-06-17" />
     <release version="0.0.9.1" date="2018-05-07" />