streamlink: 0.10.0 -> 0.12.1

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

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

These checks were done:

- built on NixOS
- ran ‘/nix/store/7rxcwgcznrsqj6kkvrxi8j2ggjx3il4v-streamlink-0.12.1/bin/.streamlink-wrapped -h’ got 0 exit code
- ran ‘/nix/store/7rxcwgcznrsqj6kkvrxi8j2ggjx3il4v-streamlink-0.12.1/bin/.streamlink-wrapped --help’ got 0 exit code
- ran ‘/nix/store/7rxcwgcznrsqj6kkvrxi8j2ggjx3il4v-streamlink-0.12.1/bin/.streamlink-wrapped -V’ and found version 0.12.1
- ran ‘/nix/store/7rxcwgcznrsqj6kkvrxi8j2ggjx3il4v-streamlink-0.12.1/bin/.streamlink-wrapped --version’ and found version 0.12.1
- ran ‘/nix/store/7rxcwgcznrsqj6kkvrxi8j2ggjx3il4v-streamlink-0.12.1/bin/streamlink -h’ got 0 exit code
- ran ‘/nix/store/7rxcwgcznrsqj6kkvrxi8j2ggjx3il4v-streamlink-0.12.1/bin/streamlink --help’ got 0 exit code
- ran ‘/nix/store/7rxcwgcznrsqj6kkvrxi8j2ggjx3il4v-streamlink-0.12.1/bin/streamlink -V’ and found version 0.12.1
- ran ‘/nix/store/7rxcwgcznrsqj6kkvrxi8j2ggjx3il4v-streamlink-0.12.1/bin/streamlink --version’ and found version 0.12.1
- found 0.12.1 with grep in /nix/store/7rxcwgcznrsqj6kkvrxi8j2ggjx3il4v-streamlink-0.12.1
- directory tree listing: https://gist.github.com/09fbfb8c035d471bd38a592acf455d9a