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

Change-Id: If969fddb3ff610170fae2ad6b797be516e98b0f4
Reviewed-on: https://go-review.googlesource.com/c/text/+/646475
Reviewed-by: Dmitri Shuralyov <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Auto-Submit: Gopher Robot <[email protected]>
Reviewed-by: David Chase <[email protected]>