Passing Moment to constructor does not work when DateOnly lib is minified

[mdsharpe]

The check date.constructor.name === 'Moment' in the DateOnly constructor does not work when the library is minified.
For example, in my app, when debugging the minified code, date.constructor.name is 'X', because the minifier has chosen to call Moment X.

One potential fix would be to inspect the _isAMomentObject property, as Moment itself does to check if an object is a Moment.

[mdsharpe]

I suspect the same problem will exist when passing instances of DateOnly to the DateOnly constructor, for the same reason.