Update Security String to 2020-12-01 am: bfe242def7

Original change: https://googleplex-android-review.googlesource.com/c/platform/build/+/12804958

Change-Id: Ibf919a022268e0a30f0cc3b53a248279751656a5
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 62c7472..4b0e9a7 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -186,7 +186,7 @@
     #  It must be of the form "YYYY-MM-DD" on production devices.
     #  It must match one of the Android Security Patch Level strings of the Public Security Bulletins.
     #  If there is no $PLATFORM_SECURITY_PATCH set, keep it empty.
-      PLATFORM_SECURITY_PATCH := 2020-11-01
+      PLATFORM_SECURITY_PATCH := 2020-12-01
 endif
 
 ifndef PLATFORM_BASE_OS