[gnome-boxes] build-aux: Remove release-notes generation script

[Felipe Borges <felipeborges src gnome org>]

commit 90cc654e33670ef0c183a815c9ea0062677e2fbb
Author: Felipe Borges <felipeborges gnome org>
Date:   Wed Jun 29 13:16:55 2022 +0200

    build-aux: Remove release-notes generation script
    
    After this conversation on Twitter https://twitter.com/wjjjjt/status/1539985014368223234
    I concluded that there are better tools to be used than what I wrote.

 build-aux/release-notes.py | 92 ----------------------------------------------
 1 file changed, 92 deletions(-)