New package request for SSHM

### Package name

sshm

### Nix package link

https://search.nixos.org/packages?channel=unstable&query=sshm&show=sshm

### Software

Hello,

Looking for the addition of the package SSHM if possible since it was recently added to unstable.
Do we have to wait until the next stable version to be included or not really?

Thanks.