component/libvnc: upgrade x11vnc to May 2023 version

unfortunately, there is no official release anymore so use a commit from
master.

component/libvnc/buildout.cfg

@@ -53,8 +53,8 @@ environment =
 
 [x11vnc]
 recipe = slapos.recipe.cmmi
-url = https://github.com/LibVNC/x11vnc/archive/0.9.16.tar.gz
-md5sum = 64172e8f896389ec963fff93415f0d93
+url = https://github.com/LibVNC/x11vnc/archive/354602cffa8edcbe813da6dfd051b96d94b3efbc.zip
+md5sum = f9a7f5e206aa0120f3337abf0910851d
 pre-configure =
   autoreconf -fiv -I ${libtool:location}/share/aclocal -I ${pkgconfig:location}/share/aclocal -I ${gettext:location}/share/aclocal
 configure-options =