chore(nix): nix flake update

Summary: I need this for another change I'm playing around with, because the
newer nixpkgs snapshot has a newer version of a tool. Just do a quick update to
get it out of the way.

Maybe one day, Dependabot can help solve this issue...

Signed-off-by: Austin Seipp <aseipp@pobox.com>
Change-Id: I803f72da8666ed75018f51ebe511737d

flake.lock

@@ -5,11 +5,11 @@
         "systems": "systems"
       },
       "locked": {
-        "lastModified": 1687171271,
-        "narHash": "sha256-BJlq+ozK2B1sJDQXS3tzJM5a+oVZmi1q0FlBK/Xqv7M=",
+        "lastModified": 1689068808,
+        "narHash": "sha256-6ixXo3wt24N/melDWjq70UuHQLxGV8jZvooRanIHXw0=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "abfb11bd1aec8ced1c9bb9adfe68018230f4fb3c",
+        "rev": "919d646de7be200f3bf08cb76ae1f09402b6f9b4",
         "type": "github"
       },
       "original": {
@@ -20,11 +20,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1687103638,
-        "narHash": "sha256-dwy/TK6Db5W7ivcgmcxUykhFwodIg0jrRzOFt7H5NUc=",
+        "lastModified": 1689078114,
+        "narHash": "sha256-osG8BrX5RpKJ7wH+vI6auOU+ctvNOblT4XXCgknK47c=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "91430887645a0953568da2f3e9a3a3bb0a0378ac",
+        "rev": "b6cc7ff8fee93789bc871a267ab876c3fca042cb",
         "type": "github"
       },
       "original": {
@@ -49,11 +49,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1687141659,
-        "narHash": "sha256-ckvEuxejYmFTyFF0u9CWV8h5u+ubuxA7vYrOw/GXRXg=",
+        "lastModified": 1689129196,
+        "narHash": "sha256-/z/Al4sFcIh5oPQWA9MclQmJR9g3RO8UDiHGaj/T9R8=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "86302751ef371597d48951983e1a2f04fe78d4ff",
+        "rev": "db8d909c9526d4406579ee7343bf2d7de3d15eac",
         "type": "github"
       },
       "original": {