feat: check for updates from github and the microsoft store - #51

Cannot convert null literal to non-nullable reference type.

Non-nullable field '_viewModel' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field '_inputStyle' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field '_historyStyle' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Nullability of reference types in type of parameter 'sender' of 'void CalculatorDisplay.ViewModel_PropertyChanged(object sender, PropertyChangedEventArgs e)' doesn't match the target delegate 'PropertyChangedEventHandler' (possibly because of nullability attributes).

Nullability of reference types in type of 'event EventHandler RelayCommand<T>.CanExecuteChanged' doesn't match implicitly implemented member 'event EventHandler? ICommand.CanExecuteChanged'.

Nullability of reference types in type of parameter 'parameter' of 'void RelayCommand<T>.Execute(object parameter)' doesn't match implicitly implemented member 'void ICommand.Execute(object? parameter)' (possibly because of nullability attributes).

Nullability of reference types in type of parameter 'parameter' of 'bool RelayCommand<T>.CanExecute(object parameter)' doesn't match implicitly implemented member 'bool ICommand.CanExecute(object? parameter)' (possibly because of nullability attributes).

Cannot convert null literal to non-nullable reference type.

Nullability of reference types in type of 'event PropertyChangedEventHandler CalculatorViewModel.PropertyChanged' doesn't match implicitly implemented member 'event PropertyChangedEventHandler? INotifyPropertyChanged.PropertyChanged'.