update nix dependencies with niv-update

* changes to nix-build output:

No version or selection state changes.
Closure size: 13 -> 13 (13 paths added, 13 paths removed, delta +0, disk usage +0B).

* changes to nix-shell output:

Version changes:
[C.]  #1  curl             7.81.0, 8.1.1 -> 7.81.0, 8.1.2
[C.]  #2  glib             2.72.0, 2.76.3, 2.76.3-bin -> 2.72.0, 2.76.4, 2.76.4-bin
[U.]  #3  hwdata           0.371 -> 0.372
[C.]  #4  iso-codes        4.11.0, 4.9.0 -> 4.15.0, 4.9.0
[C.]  #5  libassuan        2.5.5 x2 -> 2.5.5, 2.5.6
[U.]  #6  libbpf           1.2.0 -> 1.2.2
[C.]  #7  libnftnl         1.2.1, 1.2.5 -> 1.2.1, 1.2.6
[U.]  #8  librsvg          2.55.1 -> 2.56.2
[U.]  #9  libxcrypt        4.4.35 -> 4.4.36
[C.]  #10  libxml2          2.10.4, 2.9.13 -> 2.11.4, 2.9.13
[C.]  #11  p11-kit          0.24.1 x2 -> 0.24.1, 0.25.0
[C.]  #12  systemd          249.7, 253.5 -> 249.7, 253.6
[C.]  #13  systemd-minimal  249.7, 253.5 -> 249.7, 253.6
[C.]  #14  tracker          3.3.0, 3.5.1 -> 3.3.0, 3.5.3
[U*]  #15  vscodium         1.80.1.23194 -> 1.80.2.23209
Closure size: 1142 -> 1142 (851 paths added, 851 paths removed, delta +0, disk usage -16.9MiB).

nix/sources.json

@@ -5,10 +5,10 @@
         "homepage": "",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "684c17c429c42515bafb3ad775d2a710947f3d67",
-        "sha256": "1gvi4vlq1cxyi3w2mqm939c5ib5509a2ycpwyki51jdgcpkh4x9c",
+        "rev": "e6ab46982debeab9831236869539a507f670a129",
+        "sha256": "0ykjrirzxwf51d8i4pfhr5i3jyyfzn33vappdwaync0yg5i58dp4",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/684c17c429c42515bafb3ad775d2a710947f3d67.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs/archive/e6ab46982debeab9831236869539a507f670a129.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "olderIdeaNixpkgs": {