Version bump to BP1A.241210.021 [core/build_id.mk]

Change-Id: Id82471d4de406f7e230818dcf0f49cf324c56e84
diff --git a/core/build_id.mk b/core/build_id.mk
index b4cc946..cfbb958 100644
--- a/core/build_id.mk
+++ b/core/build_id.mk
@@ -18,4 +18,4 @@
 # (like "CRB01").  It must be a single word, and is
 # capitalized by convention.
 
-BUILD_ID=BP1A.241210.020
+BUILD_ID=BP1A.241210.021