Update README.md to stress the pixel-level augmentation (#1216)

Update README.md to stress the pixel-level augmentation

Co-authored-by: Mikhail Druzhinin <dipetm@gmail.com>
Co-authored-by: Vladimir Iglovikov <ternaus@users.noreply.github.com>

README.md

@@ -4,7 +4,7 @@
 
 Albumentations is a Python library for image augmentation. Image augmentation is used in deep learning and computer vision tasks to increase the quality of trained models. The purpose of image augmentation is to create new training samples from the existing data.
 
-Here is an example of how you can apply some augmentations from Albumentations to create new images from the original one:
+Here is an example of how you can apply some [pixel-level](#pixel-level-transforms) augmentations from Albumentations to create new images from the original one:
 ![parrot](https://habrastorage.org/webt/bd/ne/rv/bdnerv5ctkudmsaznhw4crsdfiw.jpeg)
 
 ## Why Albumentations