sha256 crypto digest

Examples

sha256 digest function

```rust use sha256::digest;

fn main() { let input = "hello"; let val = digest(input); assert_eq!(val, "2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824");

let input = "hello".to_string();
let val = digest(input);
assert_eq!(val, "2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824");


let input = b"hello";
let val = digest(input);
assert_eq!(val, "2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824");

} ```

sha256 try_digest function

```rust use sha256::try_digest; use std::path::Path;

fn main() { let input = Path::new("./foo.file"); let val = trydigest(input).unwrap(); asserteq!(val,"433855b7d2b96c23a6f60e70c655eb4305e8806b682a9596a200642f947259b1"); } ```