Update SKP version

Automatic commit by the RecreateSKPs bot.

TBR=
NO_MERGE_BUILDS

Review URL: https://codereview.chromium.org/1296513004
diff --git a/SKP_VERSION b/SKP_VERSION
index a21cae3..ee2b836 100644
--- a/SKP_VERSION
+++ b/SKP_VERSION
@@ -1 +1 @@
-454
\ No newline at end of file
+456
\ No newline at end of file