yozefu: remove RUSTFLAGS to use config.toml

Author: cho-m

Formula/y/yozefu.rb

@@ -28,7 +28,6 @@ def install
     ENV["OPENSSL_DIR"] = Formula["openssl@3"].opt_prefix
     ENV["OPENSSL_NO_VENDOR"] = "1"
 
-    ENV["RUSTFLAGS"] = "--cfg tokio_unstable"
     system "cargo", "install", *std_cargo_args(path: "crates/bin")
   end