fix(cargo.toml): no_std build was broken

this is caused by `getrandom` deps behind `rand/std_rng` feature flag

Cargo.toml

@@ -9,15 +9,20 @@ documentation = "https://docs.rs/schnorrkel"
 keywords = ["cryptography", "ed25519", "curve25519", "signature", "ECC"]
 categories = ["cryptography", "no-std"]
 description = "Schnorr VRF, signatures, etc. using the Ristretto group"
-exclude = [ ".gitignore", "res/*" ]
+exclude = [".gitignore", "res/*"]
 edition = "2021"
 
 [dependencies]
 aead = { version = "0.5.2", default-features = false, optional = true }
 arrayref = { version = "0.3.7", default-features = false }
 # needs to match parity-scale-code which is "=0.7.0"
 arrayvec = { version = "0.7.4", default-features = false }
-curve25519-dalek = { version = "4.1.0", default-features = false, features = ["digest", "zeroize", "precomputed-tables", "legacy_compatibility"] }
+curve25519-dalek = { version = "4.1.0", default-features = false, features = [
+    "digest",
+    "zeroize",
+    "precomputed-tables",
+    "legacy_compatibility",
+] }
 subtle = { version = "2.5.0", default-features = false }
 merlin = { version = "3.0.0", default-features = false }
 rand_core = { version = "0.6.2", default-features = false }
@@ -52,12 +57,11 @@ asm = ["sha2/asm"]
 serde = ["serde_crate", "serde_bytes", "cfg-if"]
 # We cannot make getrandom a direct dependency because rand_core makes
 # getrandom a feature name, which requires forwarding.
-getrandom = ["rand_core/getrandom", "rand/std_rng"]
+getrandom = ["rand_core/getrandom"]
 # We thus cannot forward the wasm-bindgen feature of getrandom,
 # but our consumers could depend upon getrandom and activate its
 # wasm-bindgen feature themselve, which works due to cargo features
 # being additive.
 # wasm-bindgen = ["getrandom/wasm-bindgen"]
 # See https://github.com/rust-lang/cargo/issues/9210
 # and https://github.com/w3f/schnorrkel/issues/65#issuecomment-786923588
-