sha256 is ~ 6x slower than python version

[jonalm]

On python 3.11.6

In [1]: import random

In [2]: import hashlib

In [3]: def calc_sha(bytes_):
   ...:     sha = hashlib.sha256()
   ...:     sha.update(bytes_)
   ...:     return sha
   ...:

In [4]: bytes_ =random.randbytes(10000)

In [5]: %timeit calc_sha(bytes_)
3.93 µs ± 13.5 ns per loop (mean ± std. dev. of 7 runs, 100,000 loops each)

On julia 1.10 beta

julia> using SHA
julia> using BenchmarkTools
julia> @btime sha256(a) setup=a=rand(UInt8, 10000);
  25.584 μs (4 allocations: 352 bytes)

[jonalm]

duplicate of #90