Revert "import __future__.annotations to keep up with haiku==0.0.14"

This reverts commit 00d27d4.

Author: Alnusjaponica

haiku/haiku_simple.py

@@ -8,12 +8,11 @@
 The example code is based on https://github.com/deepmind/dm-haiku/blob/master/examples/mnist.py
 """
 
-from __future__ import annotations
-
-from collections.abc import Generator
-from collections.abc import Mapping
 import os
 from typing import Any
+from typing import Generator
+from typing import Mapping
+from typing import Tuple
 import urllib
 
 import jax
@@ -120,7 +119,7 @@ def update(
         params: hk.Params,
         opt_state: OptState,
         batch: Batch,
-    ) -> tuple[hk.Params, OptState]:
+    ) -> Tuple[hk.Params, OptState]:
         """Learning rule (stochastic gradient descent)."""
         grads = jax.grad(loss)(params, batch)
         updates, opt_state = opt.update(grads, opt_state)