lxqt.compton-conf: 0.3.0 -> 0.4.0 (#42513)

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

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

These checks were done:

- built on NixOS
- Warning: no invocation of /nix/store/j1vd9mci1qp5r9fy89q6c2g5kyb3kqbw-compton-conf-0.4.0/bin/compton-conf had a zero exit code or showed the expected version
- 0 of 1 passed binary check by having a zero exit code.
- 0 of 1 passed binary check by having the new version present in output.
- found 0.4.0 with grep in /nix/store/j1vd9mci1qp5r9fy89q6c2g5kyb3kqbw-compton-conf-0.4.0
- directory tree listing: https://gist.github.com/43e23d6682f82d552941a48813aa5a63
- du listing: https://gist.github.com/d7be6d6901ffe37ae24eab147225104f