go.mod: update golang.org/x dependencies

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

Change-Id: I417637e09b09b4686ffbb79d293e80706c7bd730
Reviewed-on: https://go-review.googlesource.com/c/debug/+/590235
Auto-Submit: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

go.mod

diff --git a/go.mod b/go.mod
index d6ad626..bfee686 100644
--- a/go.mod
+++ b/go.mod
@@ -6,7 +6,7 @@
 	github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e
 	github.com/spf13/cobra v0.0.3
 	github.com/spf13/pflag v1.0.3
-	golang.org/x/sys v0.20.0
+	golang.org/x/sys v0.21.0
 )
 
 require (

go.sum

diff --git a/go.sum b/go.sum
index 3a05f8d..b1300d8 100644
--- a/go.sum
+++ b/go.sum
@@ -10,5 +10,5 @@
 github.com/spf13/cobra v0.0.3/go.mod h1:1l0Ry5zgKvJasoi3XT1TypsSe7PqH0Sj9dhYf7v3XqQ=
 github.com/spf13/pflag v1.0.3 h1:zPAT6CGy6wXeQ7NtTnaTerfKOsV6V6F8agHXFiazDkg=
 github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
-golang.org/x/sys v0.20.0 h1:Od9JTbYCk261bKm4M/mw7AklTlFYIa0bIp9BgSm1S8Y=
-golang.org/x/sys v0.20.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.21.0 h1:rF+pYz3DAGSQAxAu1CbC7catZg4ebC4UIeIhKxBZvws=
+golang.org/x/sys v0.21.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=