This reverts commit 294674c5,
that was apparently created using a newer version of po4a
than what our website requires.

Currently translated at 17.7% (11 of 62 strings)

Translation: Tails/wiki/src/news/version_3.14.1.*.po
Translate-URL: http://translate.tails.boum.org/projects/tails/wikisrcnewsversion_3141po/pt/

Currently translated at 39.0% (16 of 41 strings)

Translation: Tails/wiki/src/news/version_3.11.*.po
Translate-URL: http://translate.tails.boum.org/projects/tails/wikisrcnewsversion_311po/it/

This reverts commit 0dac4d38.

Our bin/sanity-check-website check demands that format.

This is metadata, not strings displayed as-is to users. It must be in a format
that Date::Parse can read, which means translating dates into arbitrary language
won't cut it.

refs: #11966