update crossbeam-deque to fix audit

[jkarneges]

Fixes:

Crate:     crossbeam-epoch
Version:   0.9.15
Title:     Invalid pointer dereference in `fmt::Pointer` impl for `Atomic` and `Shared` when the underlying pointer is invalid
Date:      2026-07-06
ID:        RUSTSEC-2026-0204
URL:       https://rustsec.org/advisories/RUSTSEC-2026-0204
Solution:  Upgrade to >=0.9.20
Dependency tree:
crossbeam-epoch 0.9.15
└── crossbeam-deque 0.8.3
    └── rayon-core 1.13.0
        └── rayon 1.12.0
            └── criterion 0.5.1
                └── pushpin 1.42.0-dev