Support layer shell v3+
wlroots provides up to v4. phoc only offers v2. At least one software, bemenu, requires v3.
$ printf 'asd\nqwe\n' | WAYLAND_DEBUG=1 bemenu
[2920359.323] wl_registry@2.global(9, "zwlr_layer_shell_v1", 2)
[2920359.393] -> wl_registry@2.bind(9, "zwlr_layer_shell_v1", 3, new id [unknown]@6)
[2920362.814] wl_display@1.error(wl_registry@2, 0, "invalid version for global zwlr_layer_shell_v1 (9): have 2, wanted 3")
wl_registry@2: error 0: invalid version for global zwlr_layer_shell_v1 (9): have 2, wanted 3
Originally reported to Alpine at https://gitlab.alpinelinux.org/alpine/aports/-/issues/15846