[21.11] mime-types: unrot url

[wh0]

Description of changes

Fixes #164680

Gentoo mirrors no longer distribute this file. This updates it to a surviving URL (comment).

This is not a backport of something from master. Later versions of nixpkgs have already replaced mime-types with mailcap.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
  • no, built in nixos docker image, which sets sandbox = false
• Tested, as applicable:
  • I just built it in nix repl
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
  • no, but this is a fixed-output derivation so that shouldn't affect anything
• Tested basic functionality of all binary files (usually in ./result/bin/)
  • n/a
• 22.05 Release Notes (or backporting 21.11 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
  • no user-facing changes
• Fits CONTRIBUTING.md.

[iblech]

LGTM, would merge this if I had the permissions!

Thanks to the hash check, we can trust that it's in fact the same file.