polkadot: 0.9.6 -> 0.9.7

[asymmetric]

Motivation for this change

Bump.

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/)
• 21.11 Release Notes (or backporting 21.05 Relase 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.

[RaghavSood]

Result of nixpkgs-review pr 128307 run on x86_64-linux 1

1 package built:

• polkadot

[SuperSandro2000]

is the cargo.lock file actually used anywhere?

[asymmetric]

@SuperSandro2000 excellent point. No, I was trying to use it with the features introduced in #122158, but that didn't work (one of the hashes in the Cargo.lock seems to be too short for Nix), so I went back to the usual approach, but forgot to remove the file.

Removed it, thanks for the thorough review!

/cc @danieldk in case you've seen errors like this one before.