doc: Fix a URL in the release notes for Nix 2.0
doc: Fix a URL in the release notes for Nix 2.0

ehmry/nix,NixOS/nix,shlevy/nix,rycee/nix,NixOS/nix,zimbatm/nix,pikajude/nix,peti/nix,NixOS/nix,peti/nix,dezgeg/nix,vcunat/nix,shlevy/nix,ehmry/nix,zimbatm/nix,rycee/nix,ehmry/nix,layus/nix,vcunat/nix,ehmry/nix,shlevy/nix,shlevy/nix,dtzWill/nix,pikajude/nix,dtzWill/nix,dtzWill/nix,NixOS/nix,shlevy/nix,dezgeg/nix,zimbatm/nix,layus/nix,ehmry/nix,layus/nix,zimbatm/nix,rycee/nix,pikajude/nix,layus/nix,peti/nix,vcunat/nix,dezgeg/nix,peti/nix,dezgeg/nix,layus/nix,vcunat/nix,dtzWill/nix,dtzWill/nix,peti/nix,NixOS/nix,rycee/nix,dezgeg/nix,rycee/nix,ehmry/nix