Don't require strict PyTorch and TorchVision versions (hpvm requirement)

setup.py

@@ -16,8 +16,8 @@ setuptools.setup(
     install_requires=[
         "matplotlib>=3.3",
         "networkx>=2.5",
-        "torch==1.7.1",
-        "torchvision==0.8.2",
+        "torch>=1.5.1",
+        "torchvision>=0.6",
         "tqdm>=4.50",
         "pandas>=1.1",
         "jsonpickle>=1.5",