smtube: 18.1.0 -> 18.3.0 (#38700)

Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools.

This update was made based on information from https://repology.org/metapackage/smtube/versions.

These checks were done:

- built on NixOS
- Warning: no binary found that responded to help or version flags. (This warning appears even if the package isn't expected to have binaries.)
- found 18.3.0 with grep in /nix/store/samlqqmdzqcfz0a31vfxhg4vhsj79f19-smtube-18.3.0
- directory tree listing: https://gist.github.com/e311aa1d900f0a6f815cf352c2f601a3