bird2: 2.0.1 -> 2.0.2

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

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

These checks were done:

- built on NixOS
- ran `/nix/store/b6040kgjb2ndh4sznwnd30inslcf0ngi-bird-2.0.2/bin/bird -h` got 0 exit code
- ran `/nix/store/b6040kgjb2ndh4sznwnd30inslcf0ngi-bird-2.0.2/bin/bird --help` got 0 exit code
- ran `/nix/store/b6040kgjb2ndh4sznwnd30inslcf0ngi-bird-2.0.2/bin/bird --version` and found version 2.0.2
- found 2.0.2 with grep in /nix/store/b6040kgjb2ndh4sznwnd30inslcf0ngi-bird-2.0.2
- directory tree listing: https://gist.github.com/b5a31c5299059545befb8209b15fef9d