ci: use the lilypond package provided by alpine

Signed-off-by: Davide Madrisan <[email protected]>

.github/workflows/ci.yaml

@@ -22,19 +22,12 @@ jobs:
       - id: install_pkg_deps
         run: |
           apk update
-          apk add autoconf automake bzip2 gcompat git make python3 py3-pip tar xz
-
-      - id: install_lilypond
-        run: |
-          wget -O /tmp/lilypond.tar.gz https://gitlab.com/lilypond/lilypond/-/releases/v${lilypond_version}/downloads/lilypond-${lilypond_version}-linux-x86_64.tar.gz
-          tar xzf /tmp/lilypond.tar.gz --directory=/opt
-          rm -f /tmp/lilypond.tar.gz
+          apk add autoconf automake bzip2 git lilypond make python3 py3-pip tar xz
 
       - uses: actions/checkout@v2
 
       - id: build_checks
         run: |
-          export PATH="/opt/lilypond-${lilypond_version}/bin:$PATH"
           autoreconf --install
           ./configure
 #          make dist && make