Version bump to NGI20B

Change-Id: I2b269016b4b3a314908ea3529ec96cbf31f67437
diff --git a/core/build_id.mk b/core/build_id.mk
index 0cce624..14236ae 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.
 
-export BUILD_ID=NGI20
+export BUILD_ID=NGI20B