ds_blake2b 1.0.0

A dart implement of blake2b referenced from blacknet, allows 224

0.0.1 basic implement of blake2b

• just follow the blacknet's blake2b to implment it with dart.

0.0.2 wrap a Blake2bHash for common use

0.1.0 use Uint8List instead of Int8List

0.1.2 fix bug due to a wrong implement of array copy

0.2.1 null safety, remove flutter dependency

0.2.2 bugfix: bytes2long() overflow when in chrome see Issue 1