Prepare-Release.ps1 fails with InvalidOperation and PropertyNotFoundException

[pakrym]

> .\eng\common\scripts\Prepare-Release.ps1 Azure.Core

Package Name [ Azure.Core ]
Source directory [ core ]

Assuming release is in September with release date 09/07/2021
Input the new version, or press Enter to use use current project version '1.18.0-beta.1': 1.18.0
InvalidOperation: D:\github\azure\net\eng\common\scripts\Helpers\DevOps-WorkItem-Helpers.ps1:86
Line |
  86 |        -Headers $headers -ContentType "application/json" -MaximumRetry …
     |                 ~~~~~~~~
     | The variable '$headers' cannot be retrieved because it has not been set.

PropertyNotFoundException: D:\github\azure\net\eng\common\scripts\Helpers\DevOps-WorkItem-Helpers.ps1:88
Line |
  88 |        if ($batchResponse.value)
     |            ~~~~~~~~~~~~~~~~~~~~
     | The property 'value' cannot be found on this object. Verify that the property exists.

InvalidOperation: D:\github\azure\net\eng\common\scripts\Helpers\DevOps-WorkItem-Helpers.ps1:86
Line |
  86 |        -Headers $headers -ContentType "application/json" -MaximumRetry …
     |                 ~~~~~~~~
     | The variable '$headers' cannot be retrieved because it has not been set.

PropertyNotFoundException: D:\github\azure\net\eng\common\scripts\Helpers\DevOps-WorkItem-Helpers.ps1:88
Line |
  88 |        if ($batchResponse.value)
     |            ~~~~~~~~~~~~~~~~~~~~
     | The property 'value' cannot be found on this object. Verify that the property exists.

cc @weshaggard