Add env_logger to installer

Some libraries, namely nusb, produce debug logging that we might want to
access in the field.

installer/src/main.rs

@@ -68,6 +68,7 @@ struct Serial {
 }
 
 async fn run() -> Result<(), Error> {
+    env_logger::init();
     let Args { command } = Args::parse();
 
     match command {