Delay between bullet shot with GetKey

Hello, I'm trying to make a shooting game in which you can keep the W key pressed to shoot endlessly. The problem is that there is absolutely no delay between each bullet, so this looks more like a strange laser than a proper shoot. I tried to use WaitForSeconds but it couldn't work... I would like to know where I'm wrong. Help would be greatly appreciated. :) Here's my code :

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class playerControl : MonoBehaviour {
 
     public GameObject playerBulletGO; //bullet prefab
     public GameObject bulletPosition01;
     public GameObject bulletPosition02;
     public float speed;
 
 
         // Use this for initialization
         void Start () {
         
     }
     
     // Update is called once per frame
     void Update () {
 
         if(Input.GetKey("w") || Input.GetKey("z")) {
 
             Shoot();
             StartCoroutine(ShootWait());
 
         }
 
         
         float x = Input.GetAxisRaw ("Horizontal"); // will be -1 0 or 1 (for left, no input, and right)
         float y = Input.GetAxisRaw ("Vertical"); // will be -1 0 or1 (for down, no input and up)
 
         //now based on the input we comput a direction vector and we normalize it to get a unit vector
         Vector2 direction = new Vector2 (x, y).normalized;
 
         //now we call the function that computes and set the player's position
         Move (direction);
     }
 
     void Move(Vector2 direction)
     { //here is the code for moving
     }
 
     void Shoot()
     {
         //instantiate the 1st bullet
         GameObject bullet01 = (GameObject)Instantiate(playerBulletGO);
         bullet01.transform.position = bulletPosition01.transform.position; //set the bullet initial position
 
         //instantiate the 2nd bullet
         GameObject bullet02 = (GameObject)Instantiate(playerBulletGO);
         bullet02.transform.position = bulletPosition02.transform.position; //set the bullet initial position
     }
 
     IEnumerator ShootWait()
     {
         yield return new WaitForSeconds(100.0f);
     }
 }