Update README.md

Author: rwightman

README.md

@@ -6,7 +6,7 @@
 * New weights
   * Wide-ResNet50 - 81.5 top-1 (vs 78.5 torchvision)
   * SEResNeXt50-32x4d - 81.3 top-1 (vs 79.1 cadene)
-* Support for native Torch AMP and channels_last memory format added to train/validate scripts
+* Support for native Torch AMP and channels_last memory format added to train/validate scripts (`--channels-last`, ``--native-amp` vs `--apex-amp`)
 * Models tested with channels_last on latest NGC 20.08 container. AdaptiveAvgPool in attn layers changed to mean((2,3)) to work around bug with NHWC kernel.
 
 ### Aug 12, 2020