nixos: bumped to HEAD of 21.11

nix/sources.json

@@ -24,16 +24,16 @@
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "nixpkgs": {
-        "branch": "nixos-21.05",
+        "branch": "nixos-21.11",
         "builtin": false,
         "description": "A read-only mirror of NixOS/nixpkgs tracking the released channels. Send issues and PRs to",
         "homepage": "https://github.com/NixOS/nixpkgs",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "9e86f5f7a19db6da2445f07bafa6694b556f9c6d",
-        "sha256": "0i2j7bf6jq3s13n12xahramami0n6zn1mksqgi01k7flpgyymcck",
+        "rev": "891016b5cf1998ea84852adac52c65c5ccd3e802",
+        "sha256": "0zdgxa68g8d522kq1k39s7zvwxhd9zjxpy4w04nqksp9s7iwlibx",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/9e86f5f7a19db6da2445f07bafa6694b556f9c6d.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs/archive/891016b5cf1998ea84852adac52c65c5ccd3e802.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "nixpkgsUnstable": {