The sleep value of before/after in action definition should be follow…

[Flex-Xuan]

trafficstars

What this PR does / why we need it: According to the newest spec, the before/after in sleep property should in ISO 8601 format.

Additional information (if needed):

The sleep property can be used to define time periods that workflow execution should sleep before and/or after function execution. It can have two properties:

before - defines the amount of time (literal ISO 8601 duration format or expression which evaluation results in an ISO 8601 duration) to sleep before function invocation. after - defines the amount of time (literal ISO 8601 duration format or expression which evaluation results in an ISO 8601 duration) to sleep after function invocation.