Update Security String to 2021-07-05

Bug: 188458861
Change-Id: Icdc728241b1bfe2428d1e6536a1a3b51f7a4a708
(cherry picked from commit 64b00db8f4faa2077be43c87655802e4d71964bb)
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 8e40fa7..13b85c0 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -240,7 +240,7 @@
     #  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 := 2021-06-05
+      PLATFORM_SECURITY_PATCH := 2021-07-05
 endif
 .KATI_READONLY := PLATFORM_SECURITY_PATCH