Allow stack policies to be set with CloudFormation tasks

[Slooz]

Is your feature request related to a problem? Please describe. Accidental updates to stack resources can't be prevented with CloudFormation tasks

Describe the solution you'd like Allow stack policies to be set with CloudFormation tasks

Describe alternatives you've considered

• The AWS CLI can be used to set the stack policy after the stack is created
• The AWS CLI can be used instead of the CloudFormation tasks