Fix chsh to work on macOS

.conduit.yaml

@@ -6,8 +6,8 @@
 - brew:
     - zsh
 - command:
-    - install: sudo chsh $USER -s `which zsh`
-      remove: sudo chsh $USER -s `which bash`
+    - install: sudo chsh -s `which zsh` $USER
+      remove: sudo chsh -s `which bash` $USER
 - symlink:
     - {src: zlogin, dst: ~/.zlogin}
     - {src: zlogout, dst: ~/.zlogout}