hiawatha: 10.7 -> 10.8.1

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

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

These checks were done:

- built on NixOS
- ran ‘/nix/store/pk9y5j3rn2kh3jyh6shf16x7fwif5j8b-hiawatha-10.8.1/bin/ssi-cgi -h’ got 0 exit code
- ran ‘/nix/store/pk9y5j3rn2kh3jyh6shf16x7fwif5j8b-hiawatha-10.8.1/bin/ssi-cgi -v’ and found version 10.8.1
- ran ‘/nix/store/pk9y5j3rn2kh3jyh6shf16x7fwif5j8b-hiawatha-10.8.1/bin/hiawatha -h’ got 0 exit code
- ran ‘/nix/store/pk9y5j3rn2kh3jyh6shf16x7fwif5j8b-hiawatha-10.8.1/bin/wigwam -h’ got 0 exit code
- ran ‘/nix/store/pk9y5j3rn2kh3jyh6shf16x7fwif5j8b-hiawatha-10.8.1/bin/wigwam -v’ and found version 10.8.1
- found 10.8.1 with grep in /nix/store/pk9y5j3rn2kh3jyh6shf16x7fwif5j8b-hiawatha-10.8.1
- directory tree listing: https://gist.github.com/bed64b3bf49236cbbfafddbb1f63c00a