Update Security String to 2021-10-01 am: f54f3e8118 am: 102502b088

Original change: https://googleplex-android-review.googlesource.com/c/platform/build/+/15546870

Change-Id: I3b19b07a0ba91e68c0f9a6be4cbc72f410f52b08
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 9a139da..b5c9d18 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -250,7 +250,7 @@
     #  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 := 2021-09-01
+      PLATFORM_SECURITY_PATCH := 2021-10-01
 endif
 .KATI_READONLY := PLATFORM_SECURITY_PATCH