Update Rust crate curve25519-dalek to 4.1.2

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
curve25519-dalek (source)	dev-dependencies	patch	4.1.1 -> 4.1.2

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Release Notes

dalek-cryptography/curve25519-dalek (curve25519-dalek)

### [`v4.1.2`](https://togithub.com/dalek-cryptography/curve25519-dalek/blob/HEAD/curve25519-dalek/CHANGELOG.md#412) - Fix nightly SIMD build

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