Update nixpkgs-unstable

channels/nixos-unstable/channel.json

 {
   "ref": "refs/heads/nixos-unstable",
   "url": "https://github.com/NixOS/nixpkgs/",
-  "rev": "5265d49a36bb5a18c85e6817b338b456acc3b8cc",
-  "date": "2020-10-18T20:13:06-04:00",
-  "path": "/nix/store/pir5j598afs8bis41jdshl3mga0kgq2j-nixpkgs",
-  "sha256": "0cab38mj3f5ip0hld6wqwxsg4lj6d285kw71d2c8mnk2nk5bk4q6",
+  "rev": "1dc37370c489b610f8b91d7fdd40633163ffbafd",
+  "date": "2020-10-27T01:29:36+01:00",
+  "path": "/nix/store/i9xlaxqbdb027slfbr9ymq9xw050llm9-nixpkgs",
+  "sha256": "1qvfxf83rya7shffvmy364p79isxmzcq4dxa0lkm5b3ybicnd8f4",
   "fetchSubmodules": false,
   "deepClone": false,
   "leaveDotGit": false