expired GPG key for TeX Live 2020

[Nelson H. F. Beebe]

Norbert proposes adding the texlive.asc public key to the TUG Web site.
I support that.

Also, can we get the creator(s) of the *.iso images to sign them as well?
So far, we have only *.md5 and *.sha256 checksum files for validating
correct downloads, but not for validating original contents.

Those key(s) too should be on the TUG Web site, and I'll put
them on http://www.math.utah.edu/pub/texlive-utah/ as well.

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- Nelson H. F. Beebe                    Tel: +1 801 581 5254                  -
- University of Utah                    FAX: +1 801 581 4148                  -
- Department of Mathematics, 110 LCB    Internet e-mail: beebe at math.utah.edu  -
- 155 S 1400 E RM 233                       beebe at acm.org  beebe at computer.org -
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