update nixpkgs

nix/sources.json

@@ -30,15 +30,15 @@
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "nixpkgs": {
-        "branch": "backport-154997-to-release-21.11",
+        "branch": "release-21.11",
         "description": "Nix Packages collection",
         "homepage": "",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "65ff36f30068e8571c465aa342ec553160701390",
-        "sha256": "0c95hivx5xqs09y0rm3k3y3figbhjkii2cc4nacpqxlgak92g4kp",
+        "rev": "65caf7cf6d705b61e053dc93e21249f8b7cf8dbf",
+        "sha256": "14gjc7nk2kqvzpwg6mgvp8xjsqb1nk1jdx1ld4csdqcd4knlxrkk",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/65ff36f30068e8571c465aa342ec553160701390.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs/archive/65caf7cf6d705b61e053dc93e21249f8b7cf8dbf.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "nixpkgs-21.05": {