nixops: fix

Change-Id: I15ebde319fcae3f9771da6a549e52783e0ec4409
diff --git a/WORKSPACE b/WORKSPACE
index cabd7d7..2b63406 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -53,9 +53,9 @@
 # Nix rules
 http_archive(
     name = "io_tweag_rules_nixpkgs",
-    strip_prefix = "rules_nixpkgs-364adc70f32c2b3982995fce06b334f4d159070e",
-    urls = ["https://github.com/tweag/rules_nixpkgs/archive/364adc70f32c2b3982995fce06b334f4d159070e.tar.gz"],
-    sha256 = "59cdaf64efe9391152564ccb670bd6976168fe1426ae8b9b2f676caef03a6849",
+    strip_prefix = "rules_nixpkgs-33c50ba64c11dddb95823d12f6b1324083cc5c43",
+    urls = ["https://github.com/tweag/rules_nixpkgs/archive/33c50ba64c11dddb95823d12f6b1324083cc5c43.tar.gz"],
+    sha256 = "91fedd5151bbd9ef89efc39e2172921bd7036c68cff54712a5df8ddf62bd6922",
 )
 
 # Nix packages