Bump version string for a release build

Change-Id: Ief12d044ba5ebc1fbefadf4c379e1edcdb8548b9
diff --git a/VERSION b/VERSION
index 88d3ee7..1790d35 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.8.7
+1.8.8