feat: add Swift codes for stack article

codes/swift/chapter_stack_and_queue/stack.swift

@@ -0,0 +1,39 @@
+/**
+ * File: stack.swift
+ * Created Time: 2023-01-09
+ * Author: nuomi1 (nuomi1@qq.com)
+ */
+
+@main
+enum Stack {
+    /* Driver Code */
+    static func main() {
+        /* 初始化栈 */
+        // Swift 没有内置的栈类，可以把 Array 当作栈来使用
+        var stack: [Int] = []
+
+        /* 元素入栈 */
+        stack.append(1)
+        stack.append(3)
+        stack.append(2)
+        stack.append(5)
+        stack.append(4)
+        print("栈 stack = \(stack)")
+
+        /* 访问栈顶元素 */
+        let peek = stack.last!
+        print("栈顶元素 peek = \(peek)")
+
+        /* 元素出栈 */
+        let pop = stack.removeLast()
+        print("出栈元素 pop = \(pop)，出栈后 stack = \(stack)")
+
+        /* 获取栈的长度 */
+        let size = stack.count
+        print("栈的长度 size = \(size)")
+
+        /* 判断是否为空 */
+        let isEmpty = stack.isEmpty
+        print("栈是否为空 = \(isEmpty)")
+    }
+}