mate.libmatekbd: 1.20.1 -> 1.20.2

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

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

These checks were done:

- built on NixOS

- 0 of 0 passed binary check by having a zero exit code.
- 0 of 0 passed binary check by having the new version present in output.
- found 1.20.2 with grep in /nix/store/kpfg7m5x8b5w3iydb551k94gphgymfg5-libmatekbd-1.20.2
- directory tree listing: https://gist.github.com/6ce63d695062dd787500dd9e477d0fcc
- du listing: https://gist.github.com/e78f643a66509ed04601bc722d01d2f2