remove unused dep (#14737)

substrate/Cargo.lock

@@ -3084,12 +3084,6 @@ version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
 
-[[package]]
-name = "hex-literal"
-version = "0.3.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7ebdb29d2ea9ed0083cd8cece49bbd968021bd99b0849edb4a9a7ee0fdf6a4e0"
-
 [[package]]
 name = "hkdf"
 version = "0.12.3"
@@ -6978,7 +6972,6 @@ dependencies = [
  "frame-support",
  "frame-support-test",
  "frame-system",
- "hex-literal",
  "log",
  "pallet-balances",
  "parity-scale-codec",