obs-studio: 21.1.1 -> 21.1.2 (#40660)

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

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

These checks were done:

- built on NixOS
- /nix/store/7ajk0j59wzn7pcynqchqkvlrdwnrgkdq-obs-studio-21.1.2/bin/obs passed the binary check.
- /nix/store/7ajk0j59wzn7pcynqchqkvlrdwnrgkdq-obs-studio-21.1.2/bin/.obs-wrapped passed the binary check.
- 2 of 2 passed binary check by having a zero exit code.
- 0 of 2 passed binary check by having the new version present in output.
- found 21.1.2 with grep in /nix/store/7ajk0j59wzn7pcynqchqkvlrdwnrgkdq-obs-studio-21.1.2
- directory tree listing: https://gist.github.com/f501ac763d6c76528c24a40ab59ae620
- du listing: https://gist.github.com/ed4e17e15dd316ad1aafa8e7e89394a6