xfce-update-news: Add release date and adjust separator
I find it convenient to have the date in front of me when reading NEWS
, it avoids in particular to go digging in the history to find it. It would look like this:
0.1.1 (2021-11-27) =====
The number of =
is equal to the number of characters in the version number, which gives a correct alignment in a text editor.