Dynamic arg help

When a field is "dynamic", its value is computed dynamically as the evaluation of its corresponding typescript snippet.

That snippet can be single line:

last_result.myarg

or multiline:

let x = 5;
x + 2

If it is multiline, the last statement before the final expressionMUST END WITH ; and a newline

The snippet can also be a string template:

`Hello ${params.name}, all your base ${previous_result.base_name}
belong to us`

However, the last line must always be the final expression.

The snippet can use any typescript primitives, and the following flow specific objects and functions:

• previous_result: the object containing the result of the previous step
• flow_input: the object containing the flow input arguments
• params: the object containing the current step static values
• step(n): the function returning the result of step number n. One can also use a negative n. step(0) == result of the first step , step(-1) == previous_result
• variable(path): the function returning the variable (including secrets) at given path as a string
• resource(path): the function returning the resource at a given path as an object