[release-branch.go1.15] go1.15.6

Change-Id: I9e050e1463f1bc01c04d1817aef2f81a5aac4d42
Reviewed-on: https://go-review.googlesource.com/c/go/+/275132
Run-TryBot: Carlos Amedee <carlos@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Trust: Carlos Amedee <carlos@golang.org>

VERSION

diff --git a/VERSION b/VERSION
index d4bbebb..ea3b51f 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-go1.15.5
\ No newline at end of file
+go1.15.6
\ No newline at end of file