pmd: 6.1.0 -> 6.2.0

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

This update was made based on information from https://repology.org/metapackage/pmd/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 6.2.0 with grep in /nix/store/flm3k0shklh231zj06ksx2h0zvb1kvp5-pmd-6.2.0
- found 6.2.0 in filename of file in /nix/store/flm3k0shklh231zj06ksx2h0zvb1kvp5-pmd-6.2.0
- directory tree listing: https://gist.github.com/99fc1a75766445dbe9a6459e2fe10750