[deps]: Update Rust to v2025-08-18 (#271)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
|
[rust-nightly](https://redirect.github.com/phi-ag/renovate-rust-nightly)
([source](https://rust-lang.github.io/rustup-components-history)) |
minor | `2025-05-08` -> `2025-08-18` |

---

### Configuration

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of the year before 4am on Monday" (UTC), 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
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---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
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---

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Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Daniel García <[email protected]>

Author: renovate[bot]

rust-toolchain.toml

@@ -5,4 +5,4 @@ profile = "minimal"
 
 # The following is not part of the rust-toolchain.toml format,
 # but is used by our Renovate config to manage nightly versions.
-nightly-channel = "nightly-2025-05-08"
+nightly-channel = "nightly-2025-08-18"