Update Platform Security String to 2019-03-01 for pi-dev
Bug:122541777
(cherry picked from commit a1165c3723c9d58afc83202ff63c6f691737effb)

Change-Id: I631f45a270ac830c82d3360b73061a2bb73d1bd5
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 57e5492..b64dd1b 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -231,7 +231,7 @@
     #  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 := 2019-02-05
+      PLATFORM_SECURITY_PATCH := 2019-03-01
 endif
 
 ifndef PLATFORM_SECURITY_PATCH_TIMESTAMP