Update parity-scale-codec to prepare for breaking rustc release (#6746)

This updates parity-scale-codec{-derive} to prepare for a rustc release
that would otherwise break the derive implementation:
https://github.com/rust-lang/rust/pull/73084

substrate/client/transaction-pool/graph/Cargo.toml

@@ -29,7 +29,7 @@ retain_mut = "0.1.1"
 
 [dev-dependencies]
 assert_matches = "1.3.0"
-codec = { package = "parity-scale-codec", version = "1.3.1" }
+codec = { package = "parity-scale-codec", version = "1.3.4" }
 substrate-test-runtime = { version = "2.0.0-rc5", path = "../../../test-utils/runtime" }
 criterion = "0.3"