No projects compile since updating to latest version of Unity

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class Hexagon : MonoBehaviour
6. {
7.      public Rigidbody2D rb;
8.  
9.     public float shrinkSpeed = 3f;
10.     public GameObject MyTimer;
11.  
12.     // Start is called before the first frame update
13.     void Start() {
14.         rb.rotation = Random.Range(0f, 360f);
15.         transform.localScale = Vector3.one * 10f;
16.     }
17.  
18.     // Update is called once per frame
19.     void Update() {
20.         transform.localScale -= Vector3.one * shrinkSpeed * Time.deltaTime;
21.  
22.         if (transform.localScale.x <= .05f)
23.         {
24.          
25.             Destroy(gameObject);
26.         }
27.     }
28. }
29.  

The namespace UnityEngine isn't being recognised for some reason :/

 

Facing same issue here too. Help is appreciated.

Thanks in advance.
Regards,
Shane