Update rust toolchain to 1.68 and simplify Nix stuff

nix/common.nix

@@ -1,19 +1,14 @@
-rec {
-  # * Fixed dependencies
-  pkgsSrc = fetchTarball {
-    # As of 2022-10-13
+let
+  lock = builtins.fromJSON (builtins.readFile ../flake.lock);
+  flakeCompatRev = lock.nodes.flake-compat.locked.rev;
+  flakeCompat = fetchTarball {
     url =
-      "https://github.com/NixOS/nixpkgs/archive/a3073c49bc0163fea6a121c276f526837672b555.zip";
-    sha256 = "1bz632psfbpmicyzjb8b4265y50shylccvfm6ry6mgnv5hvz324s";
+      "https://github.com/edolstra/flake-compat/archive/${flakeCompatRev}.tar.gz";
+    sha256 = lock.nodes.flake-compat.locked.narHash;
   };
-  cargo2nixSrc = fetchGit {
-    # As of 2022-10-18: two small patches over unstable branch, one for clippy and one to fix feature detection
-    url = "https://github.com/Alexis211/cargo2nix";
-    ref = "custom_unstable";
-    rev = "a7a61179b66054904ef6a195d8da736eaaa06c36";
-  };
-
-  # * Shared objects
-  cargo2nix = import cargo2nixSrc;
+  flake = ((import flakeCompat) { src = ../.; }).defaultNix;
+in rec {
+  pkgsSrc = flake.inputs.nixpkgs;
+  cargo2nix = flake.inputs.cargo2nix;
   cargo2nixOverlay = cargo2nix.overlays.default;
 }

nix/compile.nix

@@ -32,7 +32,7 @@ let
   */
   toolchainOptions = if target == null || target == "x86_64-unknown-linux-musl"
   || target == "aarch64-unknown-linux-musl" then {
-    rustVersion = "1.63.0";
+    rustVersion = "1.68.0";
     extraRustComponents = [ "clippy" ];
   } else {
     rustToolchain = pkgs.symlinkJoin {

nix/kaniko.nix

@@ -1,13 +1,13 @@
 pkgs:
 pkgs.buildGoModule rec {
   pname = "kaniko";
-  version = "1.6.0";
+  version = "1.9.2";
 
   src = pkgs.fetchFromGitHub {
     owner = "GoogleContainerTools";
     repo = "kaniko";
     rev = "v${version}";
-    sha256 = "1fnclr556avxay6pvgw5ya3xbxfnf2gv4njq2hr4fd6fcjyslq5h";
+    sha256 = "dXQ0/o1qISv+sjNVIpfF85bkbM9sGOGwqVbWZpMWfMY=";
   };
 
   vendorSha256 = null;