bcftools: 1.7 -> 1.8

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

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

These checks were done:

- built on NixOS
- ran ‘/nix/store/5nqh165r343n7954gm49wbsdwf9iic3l-bcftools-1.8/bin/plot-vcfstats -h’ got 0 exit code
- ran ‘/nix/store/5nqh165r343n7954gm49wbsdwf9iic3l-bcftools-1.8/bin/plot-vcfstats --help’ got 0 exit code
- ran ‘/nix/store/5nqh165r343n7954gm49wbsdwf9iic3l-bcftools-1.8/bin/bcftools -h’ got 0 exit code
- ran ‘/nix/store/5nqh165r343n7954gm49wbsdwf9iic3l-bcftools-1.8/bin/bcftools --help’ got 0 exit code
- ran ‘/nix/store/5nqh165r343n7954gm49wbsdwf9iic3l-bcftools-1.8/bin/bcftools help’ got 0 exit code
- found 1.8 with grep in /nix/store/5nqh165r343n7954gm49wbsdwf9iic3l-bcftools-1.8
- directory tree listing: https://gist.github.com/c9ddd760c0c740dabaabeb604fbb8a5a