build(atomix): fix netty dependency

netty-bom 4.1.70 contains the changes from pull request
netty/netty#11798, which moved the classes out
of the native modules to make sure the same classes don't end up on the
classpath multiple times. For us it should mean that we don't have to
depend on the specific native module any more but can simply depend on
the common/shared classes module.

atomix/cluster/pom.xml

@@ -69,8 +69,7 @@
     </dependency>
     <dependency>
       <groupId>io.netty</groupId>
-      <artifactId>netty-transport-native-epoll</artifactId>
-      <classifier>linux-x86_64</classifier>
+      <artifactId>netty-transport-classes-epoll</artifactId>
     </dependency>
     <dependency>
       <groupId>io.netty</groupId>