niv stable: update 1aa52711 -> e2bb73ce

## Motivation

Dependencies should be up to date.

## Changelog for stable:
Commits: [NixOS/nixpkgs@1aa52711...e2bb73ce](NixOS/nixpkgs@1aa5271...e2bb73c)

* [`83b5900a`](NixOS/nixpkgs@83b5900) fwupd: 1.3.7 → 1.3.8
* [`a2add30b`](NixOS/nixpkgs@a2add30) fwupd: 1.3.8 → 1.3.9
* [`6956305a`](NixOS/nixpkgs@6956305) borgbackup: 1.1.11 -> 1.1.13
* [`0c2ddc1d`](NixOS/nixpkgs@0c2ddc1) epkowa: fix parsing of interpreters (NixOS/nixpkgs#82909) (NixOS/nixpkgs#89506)
* [`11c84a90`](NixOS/nixpkgs@11c84a9) boot: fix order of arguments for `hasPrefix` (NixOS/nixpkgs#89751)
* [`3154bb9b`](NixOS/nixpkgs@3154bb9) roundcube: 1.4.5 -> 1.4.6
* [`cc28f9ce`](NixOS/nixpkgs@cc28f9c) i3status-rust: 0.13.1 -> 0.14.0
* [`7a7fcac4`](NixOS/nixpkgs@7a7fcac) dlib: 19.19 -> 19.20
* [`f8463ef8`](NixOS/nixpkgs@f8463ef) cargo-make: 0.30.8 -> 0.31.0

nix/sources.json

@@ -5,10 +5,10 @@
         "homepage": null,
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "1aa5271117107032e13f07bf025e3c4d26db8915",
-        "sha256": "1pws38pmzl25xn0a9wc8h4k96byknzbhx8868dxw1c818w30qa4d",
+        "rev": "e2bb73ce5f786b83e984b80199112f86b8a6cc9d",
+        "sha256": "0mpcdwhippvgsj3kj8vw35dgz94dnzgxgsfqqzcfpmvnzjc23vk7",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/1aa5271117107032e13f07bf025e3c4d26db8915.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs/archive/e2bb73ce5f786b83e984b80199112f86b8a6cc9d.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "stack2nix": {