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

Change-Id: I2db0ff828e2da1deed78924c1c5e1e3917957883
Reviewed-on: https://go-review.googlesource.com/c/mod/+/812200
Auto-Submit: Gopher Robot <gobot@golang.org>
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Mark Freeman <markfreeman@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>