vaultwarden, matrix-sliding-sync: Pin to unstable

These packages are important to keep up-to-date as clients often rely on them
being fully up-to-date.

Change-Id: I934fc7472953094b653aa1349ad28628112f1b7f
Reviewed-on: https://git.clicks.codes/c/Infra/NixFiles/+/628
Reviewed-by: Samuel Shuert <coded@clicks.codes>
Tested-by: Skyler Grey <minion@clicks.codes>
diff --git a/flake.lock b/flake.lock
index 40c87c6..4572654 100644
--- a/flake.lock
+++ b/flake.lock
@@ -453,6 +453,22 @@
         "type": "github"
       }
     },
+    "nixpkgs-unstable": {
+      "locked": {
+        "lastModified": 1712439257,
+        "narHash": "sha256-aSpiNepFOMk9932HOax0XwNxbA38GOUVOiXfUVPOrck=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "ff0dbd94265ac470dda06a657d5fe49de93b4599",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "nixpkgs_2": {
       "locked": {
         "lastModified": 1697688401,
@@ -557,6 +573,7 @@
         "nixpkgs-clicksforms": "nixpkgs-clicksforms",
         "nixpkgs-mongodb": "nixpkgs-mongodb",
         "nixpkgs-privatebin": "nixpkgs-privatebin",
+        "nixpkgs-unstable": "nixpkgs-unstable",
         "scalpel": "scalpel",
         "sops-nix": "sops-nix"
       }
diff --git a/flake.nix b/flake.nix
index 87c388a..e7b7470 100644
--- a/flake.nix
+++ b/flake.nix
@@ -3,6 +3,7 @@
 
   # input URLs
   inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-23.11";
+  inputs.nixpkgs-unstable.url = "github:nixos/nixpkgs/nixos-unstable";
   inputs.nixpkgs-clicksforms.url = "github:nixos/nixpkgs/nixos-22.05";
   inputs.flake-utils.url = "github:numtide/flake-utils";
   inputs.deploy-rs.url = "github:serokell/deploy-rs";
@@ -32,7 +33,7 @@
 
   inputs.frappix.inputs.nixpkgs.follows = "nixpkgs";
 
-  outputs = { self, nixpkgs, deploy-rs, home-manager, sops-nix, scalpel
+  outputs = { self, nixpkgs, nixpkgs-unstable, deploy-rs, home-manager, sops-nix, scalpel
     , nixpkgs-privatebin, frappix, ... }@inputs:
     let
       system = "x86_64-linux";
@@ -45,6 +46,11 @@
 
         overlays = [
           (final: prev: {
+            inherit (nixpkgs-unstable.legacyPackages.${system})
+              vaultwarden vaultwarden-postgresql # vaultwarden updates often fix compatibility with the extension
+              matrix-sliding-sync; # matrix-sliding-sync updates very fast and being on an old version breaks app compatibility
+          }) # pin-unstable
+          (final: prev: {
             inherit (nixpkgs-privatebin.legacyPackages.${system})
               privatebin pbcli;
           })