Use react icon for locking

src/main/Lock.tsx

@@ -1,5 +1,5 @@
 import React, { useEffect } from "react";
-import { faLock } from "@fortawesome/free-solid-svg-icons";
+import { LuLock } from "react-icons/lu";
 
 import { useDispatch, useSelector } from "react-redux";
 import { settings } from "../config";