primitives: add missing cargo metadata to sp-arithmetic-fuzzer (#5402)

* primitives: add missing cargo metadata to sp-arithmetic-fuzzer

* ci: add sp-arithmetic-fuzzer to unleash skip list

substrate/primitives/arithmetic/fuzzer/Cargo.toml

@@ -4,6 +4,10 @@ version = "2.0.0-alpha.5"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 license = "GPL-3.0"
+homepage = "https://substrate.dev"
+repository = "https://github.com/paritytech/substrate/"
+description = "Fuzzer for fixed point arithmetic primitives."
+documentation = "https://docs.rs/sp-arithmetic-fuzzer"
 
 [dependencies]
 sp-arithmetic = { version = "2.0.0-alpha.5", path = ".." }