Update README.md with Big Sur 11.3 Fixes

README.md

@@ -44,9 +44,20 @@ docker run -it \
     -p 50922:10022 \
     -v /tmp/.X11-unix:/tmp/.X11-unix \
     -e "DISPLAY=${DISPLAY:-:0.0}" \
+    -e GENERATE_UNIQUE=true \
+    -e MASTER_PLIST_URL=https://raw.githubusercontent.com/sickcodes/osx-serial-generator/master/config-custom.plist \
     sickcodes/docker-osx:big-sur
 ```
 
+## Important notices:
+
+**2021-05-04:** Big Sur requires an updated OpenCore.qcow2 image, simply add:
+
+```
+    -e GENERATE_UNIQUE=true \
+    -e MASTER_PLIST_URL=https://raw.githubusercontent.com/sickcodes/osx-serial-generator/master/config-custom.plist \
+```
+
 ## Technical details
 
 There currently four images, each with different use cases (explained [below](#container-images)):