v2.0.0

This release involved a lot of internal code cleanup and changes to follow modern .NET coding standards.

Part of that work involved reworking the enum used to define character classes. It has been simplified down to a simple flags enum with 4 values that can be combined to produce the required character sets. This is a breaking change as both the enum itself has been renamed from Types to CharClasses, and rather than having long enum names describing each set in the enum, callers can logical-or together their desired classes.

For example, in the first version of the library we would use Types.ALPHANUMERIC_LOWERCASE_WITH_SYMBOLS to define the character sets Lowercase, Numbers and Symbols. Now we logical-or together these three values:
CharClasses.Lowercase | CharClasses.Numbers | CharClasses.Symbols