Bump Haskell.nix to input-output-hk/haskell.nix#862 branch

Author: rvl

nix/sources.json

@@ -12,15 +12,15 @@
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "haskell.nix": {
-        "branch": "master",
+        "branch": "rvl/SRE-125/fix-hpc-cross",
         "description": "Alternative Haskell Infrastructure for Nixpkgs",
         "homepage": "https://input-output-hk.github.io/haskell.nix",
         "owner": "input-output-hk",
         "repo": "haskell.nix",
-        "rev": "662b7dbc128dfb92dd23452fc949e26bb7fc709d",
-        "sha256": "06xfcx1nh2hm69didz7syv3a35s5dh6418s4rzwi060b9xncs1j5",
+        "rev": "dcdeb646dd7ee9b79c1b016df3e95959cf3c5479",
+        "sha256": "141fwgz03grp96byyl5p3ixvnxjxqii7mxw3s98579nznpa1wb46",
         "type": "tarball",
-        "url": "https://github.com/input-output-hk/haskell.nix/archive/662b7dbc128dfb92dd23452fc949e26bb7fc709d.tar.gz",
+        "url": "https://github.com/input-output-hk/haskell.nix/archive/dcdeb646dd7ee9b79c1b016df3e95959cf3c5479.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "iohk-nix": {