Add a developer ID to the AppData XML file

Author: musicinmybrain

data/com.github.alecaddd.sequeler.appdata.xml.in.in

@@ -510,7 +510,7 @@
 			<image>https://raw.githubusercontent.com/Alecaddd/sequeler/master/data/assets/screenshots/sequeler-screenshot2.png</image>
 		</screenshot>
 	</screenshots>
-	<developer>
+	<developer id="com.alecaddd">
 		<name>Alessandro Castellani</name>
 	</developer>
 	<launchable type="desktop-id">@[email protected]</launchable>