[8u] RFR Backport 8219013: Update Apache Santuario (XML Signature) to version 2.1.3

[Elliott Baron]

Hi Paul,

On 2020-11-24 5:45 p.m., Hohensee, Paul wrote:
> Lgtm, except that I don't see a review request for the THIRD_PARTY_README change backport. Both patches should be pushed together.
> 
> Maintainers, this was a critical fix for 11.0.5, perhaps it also should be for 8u282.

Thanks for the review. I'll have the THIRD_PARTY_README update available 
for review tomorrow (Wednesday).

Thanks,
Elliott