Where is the "AddPostPipelineStageHook"

What version of CM were you using before upgrading?

 

So there is a new thing called CinemachineExtension that you need to look at. Create one, drop it in your project, and it will appear in the "Extensions" dropdown at the bottom of the vcam inspector.

Here is a sample one that does camera offset:

Code (CSharp):

1. using UnityEngine;
2. using Cinemachine;
3.  
4. /// <summary>
5. /// An add-on module for Cinemachine Virtual Camera that adds a final offset to the camera
6. /// </summary>
7. [AddComponentMenu("")] // Hide in menu
8. public class CinemachineVcamOffset : CinemachineExtension
9. {
10.     [Tooltip("Offset the camera's position by this much (camera space)")]
11.     public Vector3 m_Offset = Vector3.zero;
12.  
13.     protected override void PostPipelineStageCallback(
14.         CinemachineVirtualCameraBase vcam,
15.         CinemachineCore.Stage stage, ref CameraState state, float deltaTime)
16.     {
17.         // Apply after the camera has been aimed
18.         if (stage == CinemachineCore.Stage.Aim)
19.         {
20.             Vector3 offset = state.FinalOrientation * m_Offset;
21.             state.ReferenceLookAt += offset;
22.             state.PositionCorrection += offset;
23.         }
24.     }
25. }
26.