Location of a file containing the updated stack policy. The URL must point to a policy (max size: 16KB) located in an S3 bucket in the same
region as the stack. If you pass StackPolicyBody and StackPolicyURL, only StackPolicyBody is used. If you want to
update a stack policy during a stack update, specify an updated stack policy. For example, you can include an updated stack policy to
protect a new resource created in the stack update. If you do not specify a stack policy, the current policy that is associated with the
stack is unchanged.
Constraints:

C# |
public string StackPolicyURL { get; set; }