update nixpkgs

nix/sources.json

@@ -35,10 +35,10 @@
         "homepage": "",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "f5ed345047cf8c5ade22bc81e45adb5c0a525747",
-        "sha256": "05bz5g3q8dan6ssmsfqs28zxihxacvvi9vhny29hf8kf7zwpl09z",
+        "rev": "a44485a966bd24243fb8e7c36993d072a14b37a5",
+        "sha256": "1nzfw86gckzzl3il5lyk9xw1q3v8pzw1lisg271pg35ryj7clkbh",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/f5ed345047cf8c5ade22bc81e45adb5c0a525747.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs/archive/a44485a966bd24243fb8e7c36993d072a14b37a5.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "nixpkgs-21.05": {