Fix torchprofile import (#269)

Author: VincyZhang

docs/tutorials/pytorch/question-answering/bert-base-uncased_distilled-squad.ipynb

@@ -32,6 +32,7 @@
   },
   {
    "cell_type": "markdown",
+   "id": "0b9ed365",
    "metadata": {},
    "source": []
   },

nlp_toolkit/optimization/dynamic/evolution.py

@@ -26,8 +26,8 @@
 import timeit
 import numpy as np
 import torch
-import torchprofile
-
+from nlp_toolkit.optimization.utils.utility import LazyImport
+torchprofile = LazyImport("torchprofile")
 logger = logging.getLogger(__name__)