fix(security): pull in forgejo 1.20.6-1 early

https://codeberg.org/forgejo/forgejo/src/branch/forgejo/RELEASE-NOTES.md#1206-1

https://github.com/NixOS/nixpkgs/pull/274026
https://nixpk.gs/pr-tracker.html?pr=274026

• Added input 'release-2311':
    'github:nixos/nixpkgs/c15f414581b4eb4113eed52ed303a1e62771fb6f' (2023-12-13)

flake.lock

@@ -284,6 +284,22 @@
         "type": "github"
       }
     },
+    "release-2311": {
+      "locked": {
+        "lastModified": 1702509556,
+        "narHash": "sha256-trm+c/erCSRe+Mi2fAaI975+jrU8uhmUznx8py6N9po=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "c15f414581b4eb4113eed52ed303a1e62771fb6f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "release-23.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "agenix": "agenix",
@@ -296,6 +312,7 @@
         "nixos-flake": "nixos-flake",
         "nixpkgs": "nixpkgs",
         "nixpkgs-2205": "nixpkgs-2205",
+        "release-2311": "release-2311",
         "triton-vmtools": "triton-vmtools",
         "unstable": "unstable"
       }

flake.nix

@@ -4,6 +4,7 @@
     nixpkgs.url = "github:nixos/nixpkgs/nixos-23.11";
     unstable.url = "github:nixos/nixpkgs/nixos-unstable";
 
+    release-2311.url = "github:nixos/nixpkgs/release-23.11";
     nixpkgs-2205.url = "github:nixos/nixpkgs/nixos-22.05";
 
     nix-darwin.url = "github:lnl7/nix-darwin/master";

overlays/default.nix

@@ -7,8 +7,15 @@
     nixosModules = rec {
       overlays = ({ ... }: {
         nixpkgs.overlays = [
-          (final: prev: {
+          (final: prev:
+          let
+            release-2311 = import inputs.release-2311 {
+              system = prev.system;
+            };
+          in
+          {
             element-themes = prev.callPackage ./pkgs/element-themes { inherit (inputs) element-themes; };
+            forgejo = release-2311.forgejo;
           })
         ];
       });