Add update-nixpkgs cleanup action

[leona-ya]

This action is part of the update-nixpkgs workflow in fc-nixos-release-tools.

Important

This requires flyingcircusio/fc-nixos-release-tools#2 to be merged first.

PL-133100

@flyingcircusio/release-managers

Release process

• Created changelog entry using ./changelog.sh

PR release workflow (internal)

• PR has internal ticket
• internal issue ID (PL-…) part of branch name
• internal issue ID mentioned in PR description text
• ticket is on Platform agile board
• ticket state set to Pull request ready
• if ticket is more urgent than within the next few days, directly contact a member of the Platform team

Design notes

• Provide a feature toggle if the change might need to be adjusted/reverted quickly depending on context. Consider whether the default should be on or off. Example: rate limiting.
• All customer-facing features and (NixOS) options need to be discoverable from documentation. Add or update relevant documentation such that hosted and guided customers can understand it as well.

Security implications

• Security requirements defined? (WHERE)
  • Should not break
• Security requirements tested? (EVIDENCE)
  • Tested in fc-nixos-testing repo
    • Action run: https://github.com/flyingcircusio/fc-nixos-testing/actions/runs/12161356428/job/33915768241
    • Update PR: [24.05] Automated nixpkgs update 2024-12-04 fc-nixos-testing#27

[ctheune]

Well the security should also be: doesn't screw things up and doesn't pull in unwanted code from somewhere ... ;)