Revert back ndarray==0.16.1

Author: Radonirinaunimi

Cargo.lock

@@ -28,8 +28,9 @@ git-version = "0.3.5"
 itertools = "0.10.1"
 lhapdf = { package = "managed-lhapdf", version = "0.3.4" }
 lz4_flex = { optional = true, version = "0.9.2" }
-neopdf = "=0.3.0-alpha2"
+ndarray = "0.16.1"
 ndarray-npy = { default-features = false, features = ["npz"], optional = true, version = "0.8.1" }
+neopdf = "=0.3.0-alpha4"
 pineappl = { path = "../pineappl", version = "=1.3.3" }
 pineappl_applgrid = { optional = true, path = "../pineappl_applgrid", version = "=1.3.3" }
 pineappl_fastnlo = { optional = true, path = "../pineappl_fastnlo", version = "=1.3.3" }