Does not update when value is changed from outside

[ened]

Given code like this:

TouchSpin(
  min: 0,
  max: 99999,
  value: outsideValue,
)

Then the TouchSpin widget does not update if outsideValue is changed on the next rebuild. outsideValue may come from state, bloc etc.

Tested w/ flutter_touch_spin: ^2.0.0-nullsafety.1

[vasilich6107]

@ened the PR with fix has arrived)