chore: update niv dependencies

Author: d6e

nix/sources.json

@@ -17,10 +17,10 @@
         "homepage": "https://github.com/NixOS/nixpkgs",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "977000f149bd4ddb65bf1af09552898a0f305c72",
-        "sha256": "1ad3bviywxd64g4vwk4ppjkkajd3rfqjhnp6xcz3w0ih0sbn0rh5",
+        "rev": "cb1996818edf506c0d1665ab147c253c558a7426",
+        "sha256": "0lb6idvg2aj61nblr41x0ixwbphih2iz8xxc05m69hgsn261hk3j",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/977000f149bd4ddb65bf1af09552898a0f305c72.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs/archive/cb1996818edf506c0d1665ab147c253c558a7426.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "pre-commit-hooks.nix": {