Add correct version in AppStream File

(cherry picked from commit c4de6e27)

org.kde.kontrast.appdata.xml

@@ -83,7 +83,12 @@ SPDX-LicenseRef: CC0-1.0
   <url type="homepage">https://kde.org/applications/en/kontrast</url>
   <url type="donation">https://liberapay.com/Carl/</url>
   <releases>
-    <release version="1.0.2" date="2020-12-10"/>
+    <release version="20.12.0" date="2020-12-10">
+      <description>
+        <p>Add wayland support for choosing colors from screen.</p>
+        <p>Improve mobile support</p>
+      </description>
+    </release>
     <release version="1.0.2" date="2020-09-06">
       <description>
         <p>Fix malformed AppStream file</p>