Add temporary exception for bincode in deny.toml (#669)

[williampMSFT]

Per Matteo:
I saw a regression in our stable/deny CI job. The bincode crate is unmaintained and ⁠it has just been marked as
such.

This PR adds an exception to our deny.toml to unblock our CI for now, but we should try to migrate to another serde crate like postcard soon.

Luckily only 2 of our crates use bincode so migration is straightforward:

⁠embedded-usb-pd

• tps6699x

Cherry-pick of commit 66c758d

[Copilot]

Pull request overview

This PR adds a temporary exception to the cargo-deny configuration to allow the unmaintained bincode crate while migration to an alternative is planned. This unblocks CI that was failing due to a new RUSTSEC advisory marking bincode as unmaintained.

• Added RUSTSEC-2025-0141 exception for bincode to the ignore list in deny.toml

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[tullom]

Hold on, i think with mergebacks, we don't wish to cherry-pick commits from main back into this branch. We should merge commits so we don't have two commits with the same changes yet different commits.

[williampMSFT]

Hold on, i think with mergebacks, we don't wish to cherry-pick commits from main back into this branch. We should merge commits so we don't have two commits with the same changes yet different commits.

Works for me, I'll abandon this one and look into that