Fix gRPC dependency

Change-Id: Iddebec60218b555d8ffe39fcabd3daad0b776218
diff --git a/protocols/p4runtime/model/pom.xml b/protocols/p4runtime/model/pom.xml
index ffc4eb3..30375ec 100644
--- a/protocols/p4runtime/model/pom.xml
+++ b/protocols/p4runtime/model/pom.xml
@@ -38,7 +38,7 @@
         <dependency>
             <groupId>io.grpc</groupId>
             <artifactId>grpc-protobuf</artifactId>
-            <version>1.3.1</version>
+            <version>${grpccore.version}</version>
         </dependency>
 
         <dependency>