build(deps): bump pyo3 in /examples/namespace_package

Bumps [pyo3](https://github.com/pyo3/pyo3) from 0.19.2 to 0.20.0.
- [Release notes](https://github.com/pyo3/pyo3/releases)
- [Changelog](https://github.com/PyO3/pyo3/blob/main/CHANGELOG.md)
- [Commits](PyO3/pyo3@v0.19.2...v0.20.0)

---
updated-dependencies:
- dependency-name: pyo3
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

examples/namespace_package/Cargo.lock

@@ -18,4 +18,4 @@ path = "rust/lib.rs"  # When omitted, the value of "src/lib.rs" is assumed
 # path = "src/lib.rs"
 
 [dependencies]
-pyo3 = { version = "0.19.2", features = ["extension-module"] }
+pyo3 = { version = "0.20.0", features = ["extension-module"] }