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

Change-Id: I77f3c5560bd989f4e9c6b8c3f36e900fefe9bb0e
Reviewed-on: https://go-review.googlesource.com/c/net/+/554675
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Gopher Robot <gobot@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>