niv update: updated nixpkgs

Author: kolloch

nix/sources.json

@@ -53,10 +53,10 @@
         "homepage": "https://github.com/NixOS/nixpkgs",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "a028e2873d7fcf44e66b784b4ba061824315537f",
-        "sha256": "1pkvi5lk42vsv5m4varqbvi1n2dp7s8jvplmicnrr1gdpcminck5",
+        "rev": "0c4800d579af4ed98ecc47d464a5e7b0870c4b1f",
+        "sha256": "00gx09447gzgxlzwih4hdj51sdg62xanikkgr4bv4y7fpm98qirq",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/a028e2873d7fcf44e66b784b4ba061824315537f.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs/archive/0c4800d579af4ed98ecc47d464a5e7b0870c4b1f.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "nixpkgs-mozilla": {