Removing irrelevent feature flag

Author: ejmount

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "itertools"
-version = "0.10.5"
+version = "0.10.6"
 
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/rust-itertools/itertools"
@@ -39,10 +39,9 @@ default-features = false
 version = "0.2"
 
 [features]
-default = ["use_std", "const_generics"]
+default = ["use_std"]
 use_std = ["use_alloc", "either/use_std"]
 use_alloc = []
-const_generics = []
 
 [profile]
 bench = { debug = true }