core module should not depend on the protoc plugin module (#29)

* fix compilation error

* the core module should no depend on protoc plugin module

Author: zhxiaogg

rsocket-rpc-core/build.gradle

@@ -8,7 +8,6 @@ plugins {
 description = 'RSocket RPC Library'
 
 dependencies {
-    implementation project (':rsocket-rpc-protobuf')
     implementation 'com.google.protobuf:protobuf-java'
 
     api 'io.opentracing:opentracing-api'