Merge pull request #65 from mlabs-haskell/szg251/remove-darwin

Remove darwin CI agent

Author: szg251

hercules-ci.nix

@@ -37,7 +37,7 @@
         );
     };
 
-    ciSystems = [ "x86_64-linux" "x86_64-darwin" ];
+    ciSystems = [ "x86_64-linux" ];
   };
 }