Update rstar requirement from 0.11 to 0.12

Updates the requirements on [rstar](https://github.com/georust/rstar) to permit the latest version.
- [Release notes](https://github.com/georust/rstar/releases)
- [Commits](georust/rstar@v0.11.0...v0.12.0)

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

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

Cargo.toml

@@ -13,7 +13,7 @@ include = ["src/**/*", "LICENSE", "README.md"]
 rust-version = "1.64"
 
 [dependencies]
-rstar = { version = "0.11", optional = true }
+rstar = { version = "0.12", optional = true }
 serde = { version = "~1.0", optional = true, features = ["derive"] }
 rayon = { version = "1", optional = true }
 flate2 = { version = "1.0", optional = true }