sha3 0.2.0

SHA3 for dart. It is unbelievable that such a language doesnt has such a basic library!

0.2.0

• nullsafety
• set minimum sdk 2.12.0

0.1.2

• fix null's bit op error
• add some more tests

0.1.1

• enhance doc and code
• add and pass the shake test

0.1.0

• Initial version, created by Stagehand and pass the simple test