niv update nix-tools -b master

Author: hamishmack

nix/sources.json

@@ -66,16 +66,16 @@
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "nix-tools": {
-        "branch": "hkm/cabal-34",
+        "branch": "master",
         "builtin": false,
         "description": "Translate Cabals Generic Package Description to a Nix expression",
         "homepage": null,
         "owner": "input-output-hk",
         "repo": "nix-tools",
-        "rev": "6be18aa9a6e56bdd8f698a077b0ee18ccce3e3ee",
+        "rev": "c9c10ab889a7b7f2f5f4bb71e8786fc01d49e53e",
         "sha256": "0d5qid91j148kbgq552v6nn20r82s6v7kv789bki461icmwixlcl",
         "type": "tarball",
-        "url": "https://github.com/input-output-hk/nix-tools/archive/6be18aa9a6e56bdd8f698a077b0ee18ccce3e3ee.tar.gz",
+        "url": "https://github.com/input-output-hk/nix-tools/archive/c9c10ab889a7b7f2f5f4bb71e8786fc01d49e53e.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "nixpkgs": {