Upgrade to netty 4.1.73.Final.

Closes #717

Author: mp911de

pom.xml

@@ -35,7 +35,7 @@
 		<mariadb-jdbc.version>2.5.4</mariadb-jdbc.version>
 		<r2dbc-releasetrain.version>Borca-RELEASE</r2dbc-releasetrain.version>
 		<reactive-streams.version>1.0.3</reactive-streams.version>
-		<netty>4.1.63.Final</netty>
+		<netty>4.1.73.Final</netty>
 	</properties>
 
 	<inceptionYear>2018</inceptionYear>