Loading Dhall objects results in nondeterministic key order

[CrazyPython]

Is this an upstream dhall-rust issue?

`` ➜ ~ cat test.dhall { a = "a", b = "b" }

In [2]: dhall.load(open('test.dhall')) Out[2]: {'b': 'b', 'a': 'a'}

In [5]: dhall.load(open('test.dhall')) Out[5]: {'a': 'a', 'b': 'b'}