x509roots/fallback: update bundle

This is an automated CL which updates the NSS root bundle.

[git-generate]
go generate ./x509roots

Change-Id: Ib30b702d41dedacce835628a9dab456098be0703
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/687895
Reviewed-by: Roland Shoemaker <roland@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Gopher Robot <gobot@golang.org>

Author: gopherbot