Update SKP version

Automatic commit by the RecreateSKPs bot.

TBR=

Review URL: https://codereview.chromium.org/734493002
diff --git a/SKP_VERSION b/SKP_VERSION
index b912dc1..34bba94 100644
--- a/SKP_VERSION
+++ b/SKP_VERSION
@@ -1 +1 @@
-155
\ No newline at end of file
+156
\ No newline at end of file