Remove file with obsolete release announcement information.

This file was last (really) updated in 2003 and, unsurprisingly, information
in it is not relevant 10+ years later and most of URLs in it simply don't
exist any more (or exist but are no longer used, such as freshmeat.net, since
yesterday).

Any additional places to announce wxWidgets releases should be added to the
"Announcement" section of docs/contributing/how-to-release.md now.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76741 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775