automated: Update flake.lock

- The following Nix Flake inputs were updated:

```
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/10069ef4cf863633f57238f179a0297de84bd8d3?narHash=sha256-Q6pMP4a9ed636qilcYX8XUguvKl/0/LGXhHcRI91p0U%3D' (2025-03-06)
  → 'github:NixOS/nixpkgs/a84ebe20c6bc2ecbcfb000a50776219f48d134cc?narHash=sha256-mNqIplmEohk5jRkqYqG19GA8MbQ/D4gQSK0Mu4LvfRQ%3D' (2025-03-19)
```

Auto-generated by [update.yml][1] with the help of
[create-pull-request][2].

[1]: https://forgejo.stefka.eu/jiriks74/nix.nvim/src/branch/main/.github/workflows/update.yml
[2]: https://forgejo.stefka.eu/jiriks74/create-pull-request

flake.lock

@@ -181,11 +181,11 @@
     },
     "nixpkgs_2": {
       "locked": {
-        "lastModified": 1741851582,
+        "lastModified": 1742422364,
-        "narHash": "sha256-cPfs8qMccim2RBgtKGF+x9IBCduRvd/N5F4nYpU0TVE=",
+        "narHash": "sha256-mNqIplmEohk5jRkqYqG19GA8MbQ/D4gQSK0Mu4LvfRQ=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "6607cf789e541e7873d40d3a8f7815ea92204f32",
+        "rev": "a84ebe20c6bc2ecbcfb000a50776219f48d134cc",
         "type": "github"
       },
       "original": {