Release 5.1.1

[dpalou]

Our app is affected by the issue #58, which was fixed on 2022. However, the fix hasn't been released yet. I commented on that issue several months ago, but I didn't receive any answer.

Can you please release the 5.1.1 version of this library so we can apply the fix in our app?

Thank you!

[skibz]

I'm beginning to think it would be sensible/safer to find an alternative to this library.

libsodium itself is actively maintained, but this library is not kept in line with upstream changes.