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

Change-Id: I6c24e42c46b2378ecc6c158a98da7816c68b9565
Reviewed-on: https://go-review.googlesource.com/c/tools/+/814061
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>