UB in shuffle_avx2 and unshuffle_avx2

[EmilDohne]

Describe the bug

These two typedefs suggest that both _src and _dest should be const uint8_t*.

typedef void(* shuffle_func)(const int32_t, const int32_t, const uint8_t*, const uint8_t*);
typedef void(* unshuffle_func)(const int32_t, const int32_t, const uint8_t*, const uint8_t*);

However, the avx2 implementation does not take a const uint8_t* but instead a uint8_t*. On further inspection this seems to hold true for other implementations. To my knowledge, all calls to shuffle actually call with a non-const pointer so I think it's likely fine to make these values non-const

Logs
Below you can find a fsanitize=undefined run that points this out:

https://github.com/EmilDohne/PhotoshopAPI/actions/runs/11365462630/job/31613700651

[FrancescAlted]

This sounds reasonable to me. Would you mind providing a PR?

[EmilDohne]

I can definitely have a look at providing one!

[EmilDohne]

Fixed by #638