Upgrade to RSocket 0.2.12-RC4

Author: rstoyanchev

build.gradle

@@ -40,7 +40,7 @@ ext {
 	log4jVersion         = "2.11.2"
 	nettyVersion         = "4.1.36.Final"
 	reactorVersion       = "Dysprosium-M2"
-	rsocketVersion       = "0.12.2-RC4-SNAPSHOT"
+	rsocketVersion       = "0.12.2-RC4"
 	rxjavaVersion        = "1.3.8"
 	rxjavaAdapterVersion = "1.2.1"
 	rxjava2Version       = "2.2.9"
@@ -148,9 +148,9 @@ configure(allprojects) { project ->
 	}
 
 	repositories {
+		mavenCentral()
 		maven { url "https://repo.spring.io/libs-release" }
 		maven { url "https://repo.spring.io/milestone" } // Reactor
-		maven { url "https://oss.jfrog.org/artifactory/libs-snapshot" } // RSocket
 		mavenLocal()
 	}