Motivation for this change

The version tag for k3s is incorrect, by one character. Testing of my previous change (#81428) was insufficient to pick this up (the binary file was executable, but critical functionality was untested).
Without this, k3d is unable to pull a version of k3s to run.
Testing this round included creating and deleting a cluster, and running through the first k3d example on deploying nginx and exposing it via an ingress service (https://github.com/rancher/k3d/blob/master/docs/examples.md).

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.