Fix: Fix PHPStan error by chaining Stringable methods for email+IP

Author: Aluisio-Pires

app/Http/Requests/Auth/LoginRequest.php

@@ -80,6 +80,10 @@ public function ensureIsNotRateLimited(): void
      */
     public function throttleKey(): string
     {
-        return Str::transliterate(Str::lower($this->string('email')).'|'.$this->ip());
+        return $this->string('email')
+            ->lower()
+            ->append('|'.$this->ip())
+            ->transliterate()
+            ->value();
     }
 }