begins_with can be used to validate inputs if begin with given string

- do: milestone
     match: 'A String' # array of strings
     message: 'Some message...'
Supported Params
Param Description Required Default Message
match message to validate input with Yes  
message Message to show if the validation fails No [INPUT NAME] must begins with [MATCH]

Supported Validators:

'changeset', 'content', 'description', 'label', 'milestone', 'title'