TEST: Update dev-dependency itertools to 0.10

Author: bluss

Cargo.toml

@@ -48,7 +48,7 @@ rawpointer = { version = "0.2" }
 defmac = "0.2"
 quickcheck = { version = "0.9", default-features = false }
 approx = "0.4"
-itertools = { version = "0.9.0", default-features = false, features = ["use_std"] }
+itertools = { version = "0.10.0", default-features = false, features = ["use_std"] }
 
 [features]
 default = ["std"]