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 -3.8KiB).

* changes to nix-shell output:

Version changes:
[C.]  jerith666#1  cups                2.4.1-lib, 2.4.5-lib -> 2.4.1-lib, 2.4.6-lib
[C.]  jerith666#2  gnupg               2.3.4, 2.4.0 -> 2.3.4, 2.4.1
[C.]  jerith666#3  libXau              1.0.9 x2 -> 1.0.11, 1.0.9
[C.]  jerith666#4  libXcomposite       0.4.5 x2 -> 0.4.5, 0.4.6
[C.]  jerith666#5  libXcursor          1.2.0 x2 -> 1.2.0, 1.2.1
[U.]  jerith666#6  libXdamage          1.1.5 -> 1.1.6
[C.]  jerith666#7  libXdmcp            1.1.3 x2 -> 1.1.3, 1.1.4
[C.]  jerith666#8  libXext             1.3.4 x2 -> 1.3.4, 1.3.5
[C.]  jerith666#9  libXfixes           6.0.0 x2 -> 6.0.0, 6.0.1
[C.]  jerith666#10  libXft              2.3.4, 2.3.6 -> 2.3.4, 2.3.8
[C.]  jerith666#11  libXi               1.8 x2 -> 1.8, 1.8.1
[C.]  jerith666#12  libXinerama         1.1.4 x2 -> 1.1.4, 1.1.5
[C.]  jerith666#13  libXrandr           1.5.2 x2 -> 1.5.2, 1.5.3
[C.]  jerith666#14  libXrender          0.9.10 x2 -> 0.9.10, 0.9.11
[C.]  jerith666#15  libXtst             1.2.3 x2 -> 1.2.3, 1.2.4
[C.]  jerith666#16  libapparmor         3.0.3, 3.1.5 -> 3.0.3, 3.1.6
[C.]  jerith666#17  libcap-ng           0.8.2, 0.8.3 -> 0.8.2
[C.]  jerith666#18  libpciaccess        0.16 x2 -> 0.16, 0.17
[C.]  jerith666#19  libtiff             4.3.0, 4.5.0 -> 4.3.0, 4.5.1
[C.]  jerith666#20  libuv               1.43.0, 1.45.0, 1.45.0-dev -> 1.43.0, 1.46.0, 1.46.0-dev
[C.]  jerith666#21  libxcb              1.14 x2 -> 1.14, 1.15
[U.]  jerith666#22  libxkbfile          1.1.0 -> 1.1.2
[C.]  jerith666#23  linux-headers       5.16, 6.3 -> 5.16, 6.4
[U*]  jerith666#24  nixd                1.1.0 -> 1.2.0
[U.]  jerith666#25  nss                 3.79.4 -> 3.90
[U.]  jerith666#26  s2n-tls             1.3.45 -> 1.3.46
[C.]  jerith666#27  shadow              4.13, 4.8.1 -> 4.8.1
[C.]  jerith666#28  tpm2-tss            3.0.3, 3.2.0 -> 3.0.3, 4.0.1
[C.]  jerith666#29  util-linux-minimal  2.39-bin, 2.39-lib -> 2.39-lib, 2.39-login, 2.39-mount, 2.39-swap
[U*]  jerith666#30  vscodium            1.79.2.23166 -> 1.80.0.23188
[C.]  jerith666#31  xkeyboard-config    2.33 x2 -> 2.33, 2.39
Removed packages:
[R.]  jerith666#1  tcb  1.2
Closure size: 1143 -> 1142 (851 paths added, 852 paths removed, delta -1, disk usage -8.2MiB).

nix/sources.json

@@ -5,10 +5,10 @@
         "homepage": "",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "4a729ce4b1fe5ec4fffc71c67c96aa5184ebb462",
-        "sha256": "130qhasfvyvvb3rbmjd118j4grz8dylxsfqqj61w3ap2f3420lsl",
+        "rev": "6cee3b5893090b0f5f0a06b4cf42ca4e60e5d222",
+        "sha256": "088yi2181nfyxalkg0g84jv4jcmxclihnrcaywfmxqzz61vr8x4f",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/4a729ce4b1fe5ec4fffc71c67c96aa5184ebb462.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs/archive/6cee3b5893090b0f5f0a06b4cf42ca4e60e5d222.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "olderIdeaNixpkgs": {