[release-branch.go1.13-security] go1.13.1

Change-Id: I371ff39537fc617a2462cc947dd717b53ede7bcc
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/558790
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

VERSION

diff --git a/VERSION b/VERSION
index a5756b4..10dfea1 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-go1.13
\ No newline at end of file
+go1.13.1
\ No newline at end of file