chore: remove portable flag (#24)

Author: kevaundray

bls12_381/Cargo.toml

@@ -13,7 +13,7 @@ repository = { workspace = true }
 [dependencies]
 rayon = { workspace = true }
 
-blst = { version = "0.3.1", default-features = false, features = ["portable"] }
+blst = { version = "0.3.1", default-features = false }
 
 # __private_bench feature is used to allow us to access the base field
 blstrs = { version = "0.7.1", features = ["__private_bench"] }