Tweak 2.3.0 relnotes

Author: Luke Bakken

RELNOTES.md

@@ -4,7 +4,7 @@ Release Notes
 [v2.3.0](https://github.com/basho/riak-dotnet-client/issues?q=milestone%3Ariak-dotnet-client-2.3.0)
 ------
 
-* Add support for external load balancers via the `externalLoadBalancer` cluster option.
+* Add support for external load balancers via the `externalLoadBalancer` node option.
 * Fix issue where offline state of node not getting passed corectly.
 * [Add Riak Timeseries support](https://github.com/basho/riak-dotnet-client/pull/302)