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

Change-Id: I6b939f9a4f016b265d30fbd408f34705f89c0982
Reviewed-on: https://go-review.googlesource.com/c/text/+/626375
Reviewed-by: Dmitri Shuralyov <[email protected]>
Reviewed-by: David Chase <[email protected]>
Auto-Submit: Gopher Robot <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>