Add windows installer to appstream artifacts

This way it gets listed on apps.kde.org

data/org.kde.kdeconnect.metainfo.xml

@@ -172,7 +172,15 @@
     <value key="KDE::windows_store">https://www.microsoft.com/store/apps/9n93mrmsxbf0</value>
   </custom>
   <releases>
-    <release version="21.12.3" date="2022-03-03"/>
+    <release version="21.12.3" date="2022-03-03">
+      <artifacts>
+        <artifact type="binary" platform="win64">
+          <location>https://download.kde.org/stable/release-service/21.12.3/windows/kdeconnect-kde-21.12.3-903-windows-msvc2019_64-cl.exe</location>
+          <checksum type="sha256">ec7a9f5b3788fef774c49bc619a062a87b364e54099946a14a954637a4682318</checksum>
+          <size type="download">59447072</size>
+        </artifact>
+      </artifacts>
+    </release>
     <release version="21.12.2" date="2022-02-03"/>
     <release version="21.12.1" date="2022-01-06"/>
     <release version="21.12.0" date="2021-12-09"/>