CustomPropertyTypeMap propertySelector does now allow null

[uitmaurik]

The constructor of CustomPropertyTypeMap accepts two parameters. The propertySelector parameter is of type Func<Type, string, PropertyInfo>. If I understand correctly this means that the function must always return a PropertyInfo. Returning null is not allowed due to the project setting enable.
As the method public SqlMapper.IMemberMap? GetMember(string columnName) is the only method that uses the propertySelector and is already capable of handling a null return value, I would like to request to modify the constructor to (so changing the return type of the function from PropertyInfo to PropertyInfo?):

public CustomPropertyTypeMap(Type type, Func<Type, string, PropertyInfo?> propertySelector)

and of course the variable to:

private readonly Func<Type, string, PropertyInfo?> _propertySelector;