Use static URL for TUG.TeXLive to avoid hash changing (#12102)

* Use non-latest URL for TUG.TeXLive to avoid hash changing

* Remove TUG.TeXLive version 2020 - can't be run in unattended mode.

manifests/t/TUG/TeXLive/2020/TUG.TeXLive.yaml

@@ -1,27 +0,0 @@
-PackageIdentifier: TUG.TeXLive
-PackageVersion: 2020
-PackageName: TeX Live
-Publisher: TeX User Group
-License: LPPL/GPL
-LicenseUrl: https://www.tug.org/texlive/copying.html
-Moniker: texlive
-Tags:
-- TeX
-- LaTeX
-- ConTeXt
-- pdfTeX
-- XeTeX
-- LuaTeX
-- TeXworks
-- WEB
-- CWEB
-ShortDescription: TeX Live is intended to be a straightforward way to get up and running with the TeX document production system.
-PackageUrl: https://www.tug.org/texlive/
-Installers:
-- Architecture: neutral
-  InstallerUrl: http://ftp.ntua.gr/mirror/ctan/systems/texlive/tlnet/install-tl-windows.exe
-  InstallerSha256: 28390b0a1de0a058b2603a79ffde535c8a1d59712ae3b8f78b6e302570bdd8d9
-  InstallerType: nullsoft
-PackageLocale: en-US
-ManifestType: singleton
-ManifestVersion: 1.0.0