Allow empty stars (value = 0) with @ngx-lite/input-star-rating component

[lamstutz]

Is your feature request related to a problem? Please describe.
With a previous version, when i set formControl has a value 0, all stars become empty.
Currently, when set form control to 0 value, the component doesn't update :(

Describe the solution you'd like
Support 0 value.