chore(deps): bump io.netty:netty-handler

Bumps [io.netty:netty-handler](https://github.com/netty/netty) from 4.2.5.Final to 4.2.15.Final.
- [Release notes](https://github.com/netty/netty/releases)
- [Commits](netty/netty@netty-4.2.5.Final...netty-4.2.15.Final)

---
updated-dependencies:
- dependency-name: io.netty:netty-handler
  dependency-version: 4.2.15.Final
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

pom.xml

@@ -321,7 +321,7 @@
             <dependency>
                 <groupId>io.netty</groupId>
                 <artifactId>netty-handler</artifactId>
-                <version>4.2.5.Final</version>
+                <version>4.2.15.Final</version>
             </dependency>
             <dependency>
                 <groupId>io.netty</groupId>