Fix doc with wrong start_child arity

wkirschbaum · wkirschbaum · commit 8e18f6087988 · 2024-01-05T13:12:24.000+02:00
diff --git a/README.md b/README.md
@@ -37,7 +37,7 @@ supervisor = Supervisor.start_link(children, opts)
 
 ## Usage
 
-Use `Singleton.start_child/3` to start a unique GenServer process.
+Use `Singleton.start_child/4` to start a unique GenServer process.
 
 ```elixir
 Singleton.start_child(MyApp.Singleton, MyServer, [1], {:myserver, 1})
