chore(deps): update rust crate flume to 0.12.0 (open-telemetry#1624)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [flume](https://redirect.github.com/zesterer/flume) |
workspace.dependencies | minor | `0.11.1` -> `0.12.0` |

---

### Release Notes

<details>
<summary>zesterer/flume (flume)</summary>

###
[`v0.12.0`](https://redirect.github.com/zesterer/flume/blob/HEAD/CHANGELOG.md#0120---2025-12-08)

##### Added

- `fastrand` feature

##### Removed

- `nanorand` feature

##### Fixed

- Panic when using `Duration::MAX` as timeout

</details>

---

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rust/otap-dataflow/Cargo.toml

@@ -73,7 +73,7 @@ criterion = "0.8.0"
 data-encoding = "2.9.0"
 datafusion = { version = "51.0.0", default-features = false }
 fluke-hpack = "0.3.1"
-flume = { version = "0.11.1", default-features = false, features = ["async"] }
+flume = { version = "0.12.0", default-features = false, features = ["async"] }
 futures = "0.3.31"
 futures-core = "0.3"
 futures-channel = "0.3"