nextcloud: 13.0.1 -> 13.0.2

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

This update was made based on information from https://repology.org/metapackage/nextcloud/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 13.0.2 with grep in /nix/store/370na6b77ds8vj2qjxij4id8r5ihjpiq-nextcloud-13.0.2
- directory tree listing: https://gist.github.com/bb7d1d9b3be5379cba2c2852ec4b8e56