change mdns add-on discovery syntax (#16060)

Signed-off-by: Mark Herwege <mark.herwege@telenet.be>

bundles/org.openhab.binding.chromecast/src/main/resources/OH-INF/addon/addon.xml

@@ -18,7 +18,12 @@
 	<discovery-methods>
 		<discovery-method>
 			<service-type>mdns</service-type>
-			<mdns-service-type>_googlecast._tcp.local.</mdns-service-type>
+			<discovery-parameters>
+				<discovery-parameter>
+					<name>mdnsServiceType</name>
+					<value>_googlecast._tcp.local.</value>
+				</discovery-parameter>
+			</discovery-parameters>
 		</discovery-method>
 	</discovery-methods>