add support for keccak256

[Haxry]

closes #34

[Haxry]

@antouhou i added support for keccak256 and some basic testing for it !!

plz review it

[antouhou]

Hey @Haxry ! Thank you for the PR, amazing! Would it be possible to lock it behind a feature? Thank you a lot!

[Haxry]

@antouhou i have locked it behind a feature!! plz review!

[antouhou]

Suggested change

	tiny-keccak = { version = "2.0", features = ["keccak"] }
	tiny-keccak = { version = "2.0", features = ["keccak"], optional=true }

[antouhou]

@Haxry thank you! I've added the suggestion to the to make tiny-keccak optional, also you need to add keccak256 = ["tiny-keccak"] under the features section in cargo.toml (I can't add suggestion there, as cargo.toml hasn't been changed in the PR). Also please run cargo fmt afterward, the CI system is a bit unhappy about the newlines. I'll merge and publish a new version after that :) Thank you!

[Haxry]

@antouhou yeh let me change that

[Haxry]

@antouhou plz check now

[antouhou]

Hey @Haxry, I've published version 1.5.0 to crates.io. Thanks for the PR!