Known Issues in changelog

Author: MarieGuff

README.md

@@ -9,10 +9,17 @@ There are also pre-built binaries for Windows and/or macOS available.
 
 - ####  2021.2 Release 2 : (12.1.1 rev1 2021-12-10)
   - **Updated HD Render Pipeline / Visual Effect Graph to 12.1.1**
+  
   - **Notable Changes : **
     - Added GooBall Sample
+    
     - Jacob's ladder effect excluded from TAA for better rendering (MagicBook Sample)
-
+    
+  - **Known Issues **
+      - Prewarm delta time consideration (fixed in 2021.2.10f1)
+      - Mac M1 build: scene flickering issue 
+      - Linux build: "Vulkan - out of memory" issue
+  
 - ####  2021.2 Release 1 : (12.1.1 rev1 2021-11-29)
 
   - **Updated HD Render Pipeline / Visual Effect Graph to 12.1.1**