Merge pull request #1255 from jenkinsci/renovate/netty-monorepo

Bump netty monorepo to v4.2.15.Final

Author: uhafner

ui-tests/pom.xml

@@ -38,7 +38,7 @@
         <!-- ClassNotFoundException if omitted -->
         <groupId>io.netty</groupId>
         <artifactId>netty-bom</artifactId>
-        <version>4.2.12.Final</version>
+        <version>4.2.15.Final</version>
         <type>pom</type>
         <scope>import</scope>
       </dependency>