don't require default features for an API crate

Let the consumer define by overriding the features for the inner deps as needed.
Cargo feature resolution allows this.

Ref paritytech/polkadot#5792

client/relay-chain-inprocess-interface/Cargo.toml

@@ -27,7 +27,7 @@ sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master
 sp-state-machine = { git = "https://github.com/paritytech/substrate", branch = "master" }
 
 # Polkadot
-polkadot-cli = { git = "https://github.com/paritytech/polkadot", branch = "master" }
+polkadot-cli = { git = "https://github.com/paritytech/polkadot", branch = "master", default-features=false }
 polkadot-client = { git = "https://github.com/paritytech/polkadot", branch = "master" }
 polkadot-service = { git = "https://github.com/paritytech/polkadot", branch = "master" }