Fix build errors in examples_rclrs_minimal_client_service (#220)

Author: nnmm

examples/minimal_client_service/src/minimal_client.rs

@@ -4,7 +4,7 @@ use std::env;
 fn main() -> Result<(), Error> {
     let context = rclrs::Context::new(env::args())?;
 
-    let mut node = context.create_node("minimal_client")?;
+    let mut node = rclrs::create_node(&context, "minimal_client")?;
 
     let client = node.create_client::<example_interfaces::srv::AddTwoInts>("add_two_ints")?;
 

examples/minimal_client_service/src/minimal_client_async.rs

@@ -5,7 +5,7 @@ use std::env;
 async fn main() -> Result<(), Error> {
     let context = rclrs::Context::new(env::args())?;
 
-    let mut node = context.create_node("minimal_client")?;
+    let mut node = rclrs::create_node(&context, "minimal_client")?;
 
     let client = node.create_client::<example_interfaces::srv::AddTwoInts>("add_two_ints")?;
 

examples/minimal_client_service/src/minimal_service.rs

@@ -14,7 +14,7 @@ fn handle_service(
 fn main() -> Result<(), Error> {
     let context = rclrs::Context::new(env::args())?;
 
-    let mut node = context.create_node("minimal_service")?;
+    let mut node = rclrs::create_node(&context, "minimal_service")?;
 
     let _server = node
         .create_service::<example_interfaces::srv::AddTwoInts, _>("add_two_ints", handle_service)?;