nix: 2.7 -> unstable-2022-11-16

[milahu]

use nix with NixOS/nix#7283

fix #29
fix NixOS/nix#6572

[milahu]

on my system, nixos-rebuild switch fails with

...

nix-unstable> ran test tests/completions.sh... [PASS]
nix-unstable> ran test tests/nix-profile.sh... [PASS]
nix-unstable> ran test tests/path-from-hash-part.sh... [PASS]
nix-unstable> ran test tests/compute-levels.sh... [PASS]
nix-unstable> ran test tests/impure-derivations.sh... [PASS]
nix-unstable> installCheckPhase completed in 3 minutes 8 seconds
building the system configuration...
warning: Git tree '/home/user/etc/nixos' is dirty
error: assertion '(isNixAtLeast "2.2")' failed

       at /nix/store/qx49n5zbgid072vrhv6cjnqc94242y1r-source/nixos/modules/services/misc/nix-daemon.nix:33:5:

           32|   nixConf =
           33|     assert isNixAtLeast "2.2";
             |     ^
           34|     let

looks like we need to override version

should work with

-    version = "unstable-2022-11-16";
+    version = "2.11.1-unstable-2022-11-16";

lib.versionOlder "2.2" "unstable-2022-11-16" == false
lib.versionOlder "2.2" "2.11.1-unstable-2022-11-16" == true