go.mod: update golang.org/x dependencies

Update golang.org/x dependencies to their latest tagged versions.

Change-Id: Id1413f67816220ef8039fb933088f4b7f50d70e5
Reviewed-on: https://go-review.googlesource.com/c/oauth2/+/540817
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Gopher Robot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
diff --git a/go.mod b/go.mod
index 4dc8c87..fd0d0a3 100644
--- a/go.mod
+++ b/go.mod
@@ -11,6 +11,6 @@
 require (
 	cloud.google.com/go/compute v1.20.1 // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
-	golang.org/x/net v0.16.0 // indirect
+	golang.org/x/net v0.18.0 // indirect
 	google.golang.org/protobuf v1.31.0 // indirect
 )
diff --git a/go.sum b/go.sum
index 545169c..5a507e3 100644
--- a/go.sum
+++ b/go.sum
@@ -11,8 +11,8 @@
 github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/net v0.0.0-20190603091049-60506f45cf65/go.mod h1:HSz+uSET+XFnRR8LxR5pz3Of3rY3CfYBVs4xY44aLks=
-golang.org/x/net v0.16.0 h1:7eBu7KsSvFDtSXUIDbh3aqlK4DPsZ1rByC8PFfBThos=
-golang.org/x/net v0.16.0/go.mod h1:NxSsAGuq816PNPmqtQdLE42eU2Fs7NoRIZrHJAlaCOE=
+golang.org/x/net v0.18.0 h1:mIYleuAkSbHh0tCv7RvjL3F6ZVbLjq4+R7zbOn3Kokg=
+golang.org/x/net v0.18.0/go.mod h1:/czyP5RqHAH4odGYxBJ1qz0+CE5WZ+2j1YgoEo8F2jQ=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=