feat: update structure

cs2030s/labs/Lab4/Action.java

@@ -0,0 +1,12 @@
+/**
+ * The Action interface that can be called
+ * on an object of type T to act.
+ * Contains a single abstract method call.
+ * CS2030S Lab 4
+ * AY22/23 Semester 1
+ * @author Yadunand Prem (10B)
+ */
+
+interface Action<T> {
+  void call(T item);
+}