[21.05] nixpkgs: fix revision to latest one from nixos-21.05 branch again

[osnyx]

We accidentally locked an intermediate result while rebasing. The content of the old and new revision is semantically identical.

@flyingcircusio/release-managers

Release process

Impact:

Changelog:

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)
  • availability of code: pick a revision that is part of a git branch to prevent accidental garbage collection
  • investigate weirdly looking git histories
  • must not introduce any known regressions
• Security requirements tested? (EVIDENCE)
  • automated tests still pass