urlwatch: 2.8 -> 2.9

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

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

These checks were done:

- built on NixOS
- ran `/nix/store/2rxia8pnparqbq5fim3w2wkzd80dpnd6-urlwatch-2.9/bin/.urlwatch-wrapped -h` got 0 exit code
- ran `/nix/store/2rxia8pnparqbq5fim3w2wkzd80dpnd6-urlwatch-2.9/bin/.urlwatch-wrapped --help` got 0 exit code
- ran `/nix/store/2rxia8pnparqbq5fim3w2wkzd80dpnd6-urlwatch-2.9/bin/.urlwatch-wrapped --version` and found version 2.9
- ran `/nix/store/2rxia8pnparqbq5fim3w2wkzd80dpnd6-urlwatch-2.9/bin/urlwatch -h` got 0 exit code
- ran `/nix/store/2rxia8pnparqbq5fim3w2wkzd80dpnd6-urlwatch-2.9/bin/urlwatch --help` got 0 exit code
- ran `/nix/store/2rxia8pnparqbq5fim3w2wkzd80dpnd6-urlwatch-2.9/bin/urlwatch --version` and found version 2.9
- found 2.9 with grep in /nix/store/2rxia8pnparqbq5fim3w2wkzd80dpnd6-urlwatch-2.9
- directory tree listing: https://gist.github.com/0eda6a1b4d363b26b50e23e30e7a5397