depends: Add sodium to depends

[UdjinM6]

Should probably fix #4168

[PastaPastaPasta]

utACK

[UdjinM6]

Closing in fav of #4176

[zikarad]

Could hash of libsodium-1.0.18-stable.tar.gz be reviewed?
I can see this sha256sum:
32be348b1b7f5dd7bb890f2c867351ece5d478a3e7d2d324cbfd4aa261e71317 libsodium-1.0.18-stable.tar.gz
instead of
3c240fcd414189492d7c7dc12d2cf48f67bf04142ce2f60b620adb5bac6ca732

[UdjinM6]

libsodium-x.y.z-stable.tar.gz is the source code of x.y.z with bug fixes, security fixes and minor improvements immediately backported from the next version being currently in development. These additions over the point release are guaranteed to never change the behavior or API. Version x.y.z-stable is always fully compatible with version x.y.z. New features or breaking changes will never be introduced in a stable set of changes. libsodium-x.y.z-stable.tar.gz is an automated daily copy of the stable branch in the Git repository.

https://download.libsodium.org/libsodium/releases/README.html

Another reason why #4176 is a better solution :)