[5.8] Add method to Guard contract

 - Added methods to the guard contract, since this methods present in all Laravel Guards, but we could not use this if we will use the contact.

Author: TBlindaruk

src/Illuminate/Contracts/Auth/Guard.php

@@ -4,6 +4,20 @@
 
 interface Guard
 {
+    /**
+     * Determine if the current user is authenticated.
+     *
+     * @return \Illuminate\Contracts\Auth\Authenticatable
+     */
+    public function authenticate();
+
+    /**
+     * Determine if the guard has a user instance.
+     *
+     * @return bool
+     */
+    public function hasUser();
+
     /**
      * Determine if the current user is authenticated.
      *
@@ -47,11 +61,4 @@ public function validate(array $credentials = []);
      * @return void
      */
     public function setUser(Authenticatable $user);
-
-    /**
-     * Determine if the guard has a user instance.
-     *
-     * @return bool
-     */
-    public function hasUser();
 }