Fix webrtc README pointer in Cargo.toml

Author: lookback-hugotunius

webrtc/Cargo.toml

@@ -8,6 +8,7 @@ license = "MIT/Apache-2.0"
 documentation = "https://docs.rs/webrtc"
 homepage = "https://webrtc.rs"
 repository = "https://github.com/webrtc-rs/webrtc"
+readme = "../README.md"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html