System.ArgumentNullException: Value cannot be null

[v-jiaodi]

Describe the issue:
When executing azd up according to README.md, the error is as follows:

Repro Steps:

gh repo clone graemefoster/LockedDownChatBot
cd LockedDownChatBot
azd up

Environment:

• OS: Windows desktop.

Expected behavior:
Run azd up can pass.

@hemarina for notification.

[graemefoster]

Fixed - there was an expectation of some env variables being set. Have removed that expectation.