Prep for 2.5.2 release, use riak_pb 2.3.0.0 tag

Author: Luke Bakken

rebar.config

@@ -13,7 +13,7 @@
 ]}.
 
 {deps, [
-    {riak_pb, ".*", {git, "https://github.com/basho/riak_pb", {branch, "develop"}}}
+    {riak_pb, ".*", {git, "https://github.com/basho/riak_pb", {tag, "2.3.0.0"}}}
 ]}.
 
 {edoc_opts, [