libtasn1: upgrade 4.19.0 -> 4.20.0

libtasn1: upgrade 4.19.0 -> 4.20.0

* Noteworthy changes in release 4.20.0 (2025-02-01) [stable]
- The release tarball is now reproducible.
- We publish a minimal source-only tarball generated by 'git archive'.
- Update gnulib files and various build/maintenance fixes.
- Fix CVE-2024-12133: Potential DoS in handling of numerous SEQUENCE OF or SET
OF elements

License-Update: file COPYING.LESSER renamed to COPYING.LESSERv2 & Copyright year updated to 2025

Signed-off-by: Vijay Anusuri <vanusuri@mvista.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>