fixing some stuff

src/main/java/dev/ksan/botinator/Main.java

@@ -34,13 +34,20 @@ public class Main extends ListenerAdapter {
             System.exit(1);
         }
 
+        String lavalinkPassword = System.getenv("LAVALINK_PASSWORD");
+        if (lavalinkPassword == null || lavalinkPassword.isBlank()) {
+            System.err.println("ERROR: environment variable LAVALINK_PASSWORD is not set. "
+                    + "Set it to your Lavalink server password (see .env) and try again.");
+            System.exit(1);
+        }
+
         // Lavalink client must be created before JDA so we can plug in the voice
         // interceptor. Its node points at a running Lavalink v4 server.
         LavalinkClient lavalink = new LavalinkClient(Helpers.getUserIdFromToken(token));
         lavalink.addNode(new NodeOptions.Builder()
                 .setName("main")
                 .setServerUri(getenv("LAVALINK_URI", "ws://localhost:2333"))
-                .setPassword(getenv("LAVALINK_PASSWORD", "youshallnotpass"))
+                .setPassword(lavalinkPassword)
                 .build());
 
         MusicManager musicManager = new MusicManager(lavalink);