Update Rust crate ml-kem to v0.2.1

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
ml-kem (source)	dependencies	patch	=0.2.0 -> =0.2.1

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Configuration

📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

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• If you want to rebase/retry this PR, check this box

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[renovate]

⚠️ Artifact update problem

Renovate failed to update an artifact related to this branch. You probably do not want to merge this PR as-is.

♻ Renovate will retry this branch, including artifacts, only when one of the following happens:

• any of the package files in this branch needs updating, or
• the branch becomes conflicted, or
• you click the rebase/retry checkbox if found above, or
• you rename this PR's title to start with "rebase!" to trigger it manually

The artifact failure details are included below:

File name: security-monitor/Cargo.lock

Command failed: cargo update --config net.git-fetch-with-cli=true --manifest-path security-monitor/rust-crates/riscv_cove_tap/Cargo.toml --package [email protected] --precise 0.2.1
error: package ID specification `[email protected]` did not match any packages
help: there are similar package ID specifications:

  [email protected]