message: update rand dependency 0.7 -> 0.8
diff: @@ -37,7 +37,7 @@ blake2 = { version = "0.9", optional = true }
  #
  # Sadly couldn't be marked as dev-dependency.
  # Never use this crate outside of the off-chain environment!
  -rand = { version = "0.7", default-features = false, features = ["alloc"], optional = true }
  +rand = { version = "0.8", default-features = false, features = ["alloc"], optional = true }
  scale-info = { version = "0.4", default-features = false, features = ["derive"], optional = true }
  [features]
  @@ -53,6 +53,7 @@ std = [
  "scale-info/std",
  "rand",
  "rand/std",
  + "rand/std_rng",
  "num-traits/std",
  # Enables hashing crates for off-chain environment.
  "sha2",
  