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:
rust-lang/rust#73084

Author: bkchr

Cargo.toml

@@ -12,7 +12,7 @@ repository = "https://github.com/paritytech/substrate/"
 targets = ["x86_64-unknown-linux-gnu"]
 
 [dependencies]
-codec = { package = "parity-scale-codec", version = "1.3.1", default-features = false, features = ["derive"] }
+codec = { package = "parity-scale-codec", version = "1.3.4", default-features = false, features = ["derive"] }
 sp-inherents = { version = "2.0.0-rc5", default-features = false, path = "../../primitives/inherents" }
 sp-authorship = { version = "2.0.0-rc5", default-features = false, path = "../../primitives/authorship" }
 sp-std = { version = "2.0.0-rc5", default-features = false, path = "../../primitives/std" }