cloudflared: use go 1.20, 1.21 is too new

[misuzu]

Description of changes

Fix build failure: https://hydra.nixos.org/build/238910412

unpacking sources
unpacking source archive /nix/store/3agjbs5qkgglgd7hf13xk8kkv4d0sx67-source
source root is source
patching sources
updateAutotoolsGnuConfigScriptsPhase
configuring
building
Building subPackage ./carrier
Building subPackage ./cfapi
Building subPackage ./cfio
Building subPackage ./cmd/cloudflared
# github.com/quic-go/quic-go/internal/qtls
vendor/github.com/quic-go/quic-go/internal/qtls/go121.go:5:13: cannot use "The version of quic-go you're using can't be built on Go 1.21 yet. For more details, please see https://github.com/quic-go/quic-go/wiki/quic-go-and-Go-versions." (untyped string constant "The version of quic-go you're using can't be built on Go 1.21 yet. F...) as int value in variable declaration

Upstream issue: cloudflare/cloudflared#1054

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• 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
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.11 Release Notes (or backporting 23.05 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
• Fits CONTRIBUTING.md.

[kirillrdy]

Result of nixpkgs-review pr 263841 run on aarch64-linux 1

1 package built:

• cloudflared