deps: notify 8.2.0 to drop mio 0.8.11 (NetBSD build fix)

rockbox-library used notify 6.1.1, which pulls mio 0.8.11. mio 0.8's
kqueue code types the kevent udata field as intptr_t on NetBSD, clashing
with libc's *mut c_void, so it fails to compile there. notify 8.2.0 uses
mio 1.2.1 (fixed) + the kqueue crate, so rockbox-cli/rockbox-server now
resolve to mio 1.2.1 only.

notify 8 requires walkdir ^2.4, which the deno submodule pinned to
=2.3.2; the submodule is bumped to =2.5.0 (pushed to rockbox-deno main)
and its pointer updated here.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>