Update ndarray requirement from 0.15 to 0.16

Updates the requirements on [ndarray](https://github.com/rust-ndarray/ndarray) to permit the latest version.
- [Release notes](https://github.com/rust-ndarray/ndarray/releases)
- [Changelog](https://github.com/rust-ndarray/ndarray/blob/master/RELEASES.md)
- [Commits](rust-ndarray/ndarray@ndarray-rand-0.15.0...0.16.0)

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

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

Cargo.toml

@@ -18,7 +18,7 @@ exclude = ["./github"]
 codecov = { repository = "petabi/petal-neighbors", service = "github" }
 
 [dependencies]
-ndarray = "0.15"
+ndarray = "0.16"
 num-traits = "0.2"
 ordered-float = "4"
 thiserror = "1"