gopls: update go.mod for gopls/v0.5.1

Change-Id: I3ecba2f98b094c7aa72abaf5217909bd4df6df61
Reviewed-on: https://go-review.googlesource.com/c/tools/+/258291
Trust: Rebecca Stambler <rstambler@golang.org>
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
diff --git a/gopls/go.mod b/gopls/go.mod
index 09d6ce1..d646362 100644
--- a/gopls/go.mod
+++ b/gopls/go.mod
@@ -4,7 +4,7 @@
 
 require (
 	github.com/sergi/go-diff v1.1.0
-	golang.org/x/tools v0.0.0-20200925151336-0322e45e3e6c
+	golang.org/x/tools v0.0.0-20200929211117-1e1ba560f0b0
 	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1
 	honnef.co/go/tools v0.0.1-2020.1.5
 	mvdan.cc/gofumpt v0.0.0-20200802201014-ab5a8192947d