[tldoc] stale translations for TeX Live

[Karl Berry]

Going by the PO-Revision-Date fields (all the information easily
available), some of the TeX Live .po translations weren't updated this
year; others haven't been updated for several years. The Chinese
translations not since 2009?!

I've listed the people who were updating these, last I knew.
(Sorry about ASCII-fying names.)

If you need to step down from updating the translations.  Or conversely,
if you're able to bring your .po up to date, that would be great, of
course. There's no huge urgency in doing the updates, but I'd like to
seek new volunteers where necessary, so please let me know.

Thanks,
Karl

da.po "PO-Revision-Date: 2021-05-05 10:13+0200\n" (Palle Jorgenson)
vi.po "PO-Revision-Date: 2021-03-13 11:02+0100\n" (Anh Huynh)
it.po "PO-Revision-Date: 2021-03-22 06:20+0100\n" (Marco Pallante)

sr.po "PO-Revision-Date: 2019-10-23 02:13+0300\n" (Nikola Lecic)
es.po "PO-Revision-Date: 2019-03-30 17:58-0400\n" (Carlos Enriquez Figueras)
uk.po "PO-Revision-Date: 2019-03-23 09:02+0200\n" (Andriy Bandura)

zh_CN.po "PO-Revision-Date: 2009-09-22 12:54+0800\n" (Jiang Jiang)
zh_TW.po "PO-Revision-Date: 2009-09-03 12:34+0200\n" (unmaintained)