Feature to skip empty/missing values

[OfirYaron]

Is your feature request related to a problem? Please describe.
When value is bound to an environment or secret who's missing, the step will count as fail, when in some cases it's not required

Describe the solution you'd like
an option to skip empty/missing values

Describe alternatives you've considered
added an optional field/setting to skip empty value

Additional context
PR already open on the subject:
#27