allow for mixed precision training with fp16 flag

setup.py

@@ -3,7 +3,7 @@ from setuptools import setup, find_packages
 setup(
   name = 'denoising-diffusion-pytorch',
   packages = find_packages(),
-  version = '0.2.3',
+  version = '0.2.4',
   license='MIT',
   description = 'Denoising Diffusion Probabilistic Models - Pytorch',
   author = 'Phil Wang',
@@ -17,7 +17,7 @@ setup(
     'einops',
     'numpy',
     'pillow',
-    'torch>=1.6',
+    'torch',
     'torchvision',
     'tqdm'
   ],