Added `diffusers` to conda-forge and updated README for installation instruction (#129)

add instruction to install with conda
Co-authored-by: Anton Lozhkov <anton@huggingface.co>

README.md

@@ -120,11 +120,17 @@ The class provides functionality to compute previous image according to alpha, b
 
 ## Installation
 
+**With `pip`**
+    
 ```bash
 pip install diffusers  # should install diffusers 0.1.3
 ```
 
+**With `conda`**
 
+```sh
+conda install -c conda-forge diffusers
+```
 
 ## In the works