x509roots/fallback: update bundle

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

Change-Id: Ic70152e674c60e48e85d96eab244add9b4fa5eb8
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/512595
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Gopher Robot <gobot@golang.org>
Auto-Submit: Gopher Robot <gobot@golang.org>
Reviewed-by: Roland Shoemaker <roland@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

Author: gopherbot