Update Rust crate httptest to 0.16.4 (#1865)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [httptest](https://redirect.github.com/ggriffiniii/httptest) |
workspace.dependencies | patch | `0.16.3` → `0.16.4` |

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### Release Notes

<details>
<summary>ggriffiniii/httptest (httptest)</summary>

###
[`v0.16.4`](https://redirect.github.com/ggriffiniii/httptest/compare/v0.16.3...v0.16.4)

[Compare
Source](https://redirect.github.com/ggriffiniii/httptest/compare/v0.16.3...v0.16.4)

</details>

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Cargo.lock

@@ -66,7 +66,7 @@ futures = "0.3"
 futures-core = "0.3"
 hex = "0.4"
 http = "1.4.0"
-httptest = "0.16.3"
+httptest = "0.16.4"
 human_bytes = "0.4.3"
 humantime = "2.3.0"
 hyper = { version = "1", features = [ "full" ] }