Update portable-atomic-util requirement from 0.1.4 to 0.2.0

Updates the requirements on [portable-atomic-util](https://github.com/taiki-e/portable-atomic) to permit the latest version.
- [Release notes](https://github.com/taiki-e/portable-atomic/releases)
- [Changelog](https://github.com/taiki-e/portable-atomic/blob/main/CHANGELOG.md)
- [Commits](taiki-e/portable-atomic@portable-atomic-util-0.1.4...portable-atomic-util-0.2.0)

---
updated-dependencies:
- dependency-name: portable-atomic-util
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Cargo.toml

@@ -26,7 +26,7 @@ unexpected_cfgs = { level = "warn", check-cfg = ['cfg(loom)'] }
 [dependencies]
 concurrent-queue = { version = "2.4.0", default-features = false }
 pin-project-lite = "0.2.12"
-portable-atomic-util = { version = "0.1.4", default-features = false, optional = true, features = ["alloc"] }
+portable-atomic-util = { version = "0.2.0", default-features = false, optional = true, features = ["alloc"] }
 
 [target.'cfg(not(target_family = "wasm"))'.dependencies]
 parking = { version = "2.0.0", optional = true }