fix step to walk in NOC_I_05_NoiseWalk

Author: 201flaviosilva

chp00_introduction/NOC_I_05_NoiseWalk/sketch.js

@@ -11,7 +11,7 @@ function setup() {
 }
 
 function draw() {
-  walker.step();
+  walker.walk();
   walker.display();
 }