Clone Lilypond from the upstream repository and support updates

.config/setup/43-install-emacs-lilypond-mode.sh

@@ -7,6 +7,6 @@ projdir="$(systemd-path user)"/Projects
 mkdir --parents "${projdir}"
 rm --force --recursive "${projdir}/lilypond"
 cd "${projdir}" || exit
-git clone --depth=1 https://github.com/lilypond/lilypond
+git clone https://git.savannah.gnu.org/git/lilypond
 cd lilypond || exit
 python3 scripts/build/lilypond-words.py --el --dir=elisp/