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

Change-Id: Ib25f5b0dfa47e4446cdef2b615a71fd558e32e4c
Reviewed-on: https://go-review.googlesource.com/c/mod/+/814842
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
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: Neal Patel <nealpatel@google.com>