x509roots/fallback: update bundle

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

[git-generate]
go generate ./x509roots

Change-Id: Icb71f9f7c509dc6f49ad4385aa287bd6a8966523
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/681915
Auto-Submit: Gopher Robot <gobot@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Roland Shoemaker <roland@golang.org>

Author: gopherbot