Update unwinding requirement from 0.1.6 to 0.2.0 in /tests/no-std

Updates the requirements on [unwinding](https://github.com/nbdd0121/unwinding) to permit the latest version.
- [Commits](nbdd0121/unwinding@v0.1.7...v0.2.0)

---
updated-dependencies:
- dependency-name: unwinding
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Cargo.toml

@@ -78,4 +78,4 @@ backtrace = ["stdio", "unwinding", "unwinding/hide-trace"]
 portable-atomic = { version = "1.3", optional = true, default-features = false, features = ["require-cas"] }
 
 # Not public optional features.
-unwinding = { version = "0.1.6", optional = true, default-features = false, features = ["unwinder"] }
+unwinding = { version = "0.2.0", optional = true, default-features = false, features = ["unwinder"] }