x509roots/fallback: update bundle

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

Change-Id: I3a4388574221a77486b184e73f4b776ff0afc09f
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/646215
Auto-Submit: Gopher Robot <gobot@golang.org>
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>

Author: gopherbot