Added a note about the URP-8.2.0 Branch

Author: yahiaetman

README.md

@@ -32,6 +32,8 @@ Other custom effects in samples but not used in screenshots:
 * Unity 2020.2
 * URP 10.2.2
 
+**Note:** There is a branch with support for URP 8.2.0 (Unity 2020.1) which you can find [here](https://github.com/yahiaetman/URPCustomPostProcessingStack/tree/URP-8.2.0).
+
 ## Features
 
 * Conveniently add custom post processing effects à la [PPSv2](https://github.com/Unity-Technologies/PostProcessing) and [HDRP's Custom Post Process](https://docs.unity3d.com/Packages/com.unity.render-pipelines.high-definition@8.2/manual/Custom-Post-Process.html).