Make ndarray dep dev-only

Author: aseyboldt

Cargo.toml

@@ -28,7 +28,6 @@ itertools = "0.11.0"
 crossbeam = "0.8.2"
 thiserror = "1.0.40"
 rayon = "1.7.0"
-ndarray = "0.15.6"
 arrow2 = { version = "0.17.2", optional = true }
 rand_chacha = "0.3.1"
 anyhow = "1.0.71"
@@ -39,6 +38,7 @@ pretty_assertions = "1.3.0"
 criterion = "0.5.1"
 nix = "0.26.2"
 approx = "0.5.1"
+ndarray = "0.15.6"
 
 [[bench]]
 name = "sample"