nix: move to separate poetry2nix flake input

As upstream nixos-unstable (23.11) is dropping in-tree poetry2nix, we're
switching to using it from a separate input.

flake.lock

@@ -1,12 +1,33 @@
 {
   "nodes": {
+    "nix-github-actions": {
+      "inputs": {
+        "nixpkgs": [
+          "poetry2nix",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1698974481,
+        "narHash": "sha256-yPncV9Ohdz1zPZxYHQf47S8S0VrnhV7nNhCawY46hDA=",
+        "owner": "nix-community",
+        "repo": "nix-github-actions",
+        "rev": "4bb5e752616262457bc7ca5882192a564c0472d2",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "nix-github-actions",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1694767346,
+        "lastModified": 1699099776,
-        "narHash": "sha256-5uH27SiVFUwsTsqC5rs3kS7pBoNhtoy9QfTP9BmknGk=",
+        "narHash": "sha256-X09iKJ27mGsGambGfkKzqvw5esP1L/Rf8H3u3fCqIiU=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "ace5093e36ab1e95cb9463863491bee90d5a4183",
+        "rev": "85f1ba3e51676fa8cc604a3d863d729026a6b8eb",
         "type": "github"
       },
       "original": {
@@ -16,13 +37,54 @@
         "type": "github"
       }
     },
+    "poetry2nix": {
+      "inputs": {
+        "flake-utils": [
+          "utils"
+        ],
+        "nix-github-actions": "nix-github-actions",
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "systems": "systems",
+        "treefmt-nix": "treefmt-nix"
+      },
+      "locked": {
+        "lastModified": 1699840429,
+        "narHash": "sha256-MmnYcEht/ACXT1jVz+52PKFaX3ahz7+utOSjOVVdgGs=",
+        "owner": "nix-community",
+        "repo": "poetry2nix",
+        "rev": "4b235496501eacebc1afe7cc9bd8ce9cf88502e7",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "poetry2nix",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "nixpkgs": "nixpkgs",
+        "poetry2nix": "poetry2nix",
         "utils": "utils"
       }
     },
     "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "id": "systems",
+        "type": "indirect"
+      }
+    },
+    "systems_2": {
       "locked": {
         "lastModified": 1681028828,
         "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
@@ -37,9 +99,30 @@
         "type": "github"
       }
     },
+    "treefmt-nix": {
+      "inputs": {
+        "nixpkgs": [
+          "poetry2nix",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1699786194,
+        "narHash": "sha256-3h3EH1FXQkIeAuzaWB+nK0XK54uSD46pp+dMD3gAcB4=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "e82f32aa7f06bbbd56d7b12186d555223dc399d1",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
+      }
+    },
     "utils": {
       "inputs": {
-        "systems": "systems"
+        "systems": "systems_2"
       },
       "locked": {
         "lastModified": 1694529238,

flake.nix

@@ -4,14 +4,20 @@
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
     utils.url = "github:numtide/flake-utils";
+    poetry2nix = {
+      url = "github:nix-community/poetry2nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+      inputs.flake-utils.follows = "utils";
+    };
   };
 
-  outputs = { self, nixpkgs, utils }:
+  outputs = { self, nixpkgs, utils, ... }@inputs:
     utils.lib.eachDefaultSystem (system:
       let 
         pkgs = import nixpkgs {
           inherit system;
           config.allowUnfree = true;
+          overlays = [ inputs.poetry2nix.overlays.default ];
         };
       in {
         packages.bookwyrm = pkgs.callPackage ./nix/default.nix { };