fix: compile error when using enum in flutter

libs/flutter_rust_bridge_codegen/src/main.rs

@@ -0,0 +1,19 @@
+use env_logger::Env;
+use log::info;
+use structopt::StructOpt;
+
+use lib_flutter_rust_bridge_codegen::{frb_codegen, Opts};
+
+fn main() {
+    let opts = Opts::from_args();
+    env_logger::Builder::from_env(Env::default().default_filter_or(if opts.verbose {
+        "debug"
+    } else {
+        "info"
+    }))
+    .init();
+
+    frb_codegen(opts).unwrap();
+
+    info!("Now go and use it :)");
+}