Add note on local.grpc.port

spring-grpc-docs/src/main/antora/modules/ROOT/pages/client.adoc

@@ -142,6 +142,15 @@ SimpleGrpc.SimpleBlockingStub stub(GrpcChannelFactory channels, @LocalGrpcPort i
 }
 ----
 
+The channel can be configured via `application.properties` as well, by using the ``${local.grpc.port}` property placeholder.
+The `@Bean` where you create the stub must still be `@Lazy` for the same reason as above.
+For example:
+
+[source,properties]
+----
+spring.grpc.client.channels.local.address=0.0.0.0:${local.grpc.port}
+----
+
 [[client-interceptor]]
 == Client Interceptors