deskutils/fet: update to 6.8.7

ChangeLog: https://lalescu.ro/liviu/fet/news.html

17 March 2023, FET 6.8.7 released

• Updated to Qt 6.4.3.
• Improved the method of selection of the interface font.
• Updated the Italian translation, by Andrea Primiani, who is the new translator.

5 March 2023, FET 6.8.6 released

• Code cleanup.
• Minor corrections in the English text.

23 February 2023, FET 6.8.5 released

• Code cleanup.
• Minor corrections in the English text,

8 February 2023, FET 6.8.4 released

• Code cleanup.
  • Minor corrections in the English text. The typos were found using a program written by Volker Dirr.
  • Updated the Greek translation.
  • Minor corrections in the Romanian translation. The typos were found using a program written by Volker Dirr.
  • Updated the German translation, by Volker Dirr.

PR: 270321
Reported by: uzsolt@uzsolt.hu (maintainer)