Update Str::equals to be binary safe

Author: iamface

src/Str.php

@@ -61,9 +61,9 @@ public static function endsWith(string $string, string $suffix, bool $caseSensit
     public static function equals(string $a, string $b, bool $caseSensitive = true): bool
     {
         if ($caseSensitive) {
-            return $a === $b;
+            return strcmp($a, $b) === 0;
         } else {
-            return strtolower($a) === strtolower($b);
+            return strcasecmp($a, $b) === 0;
         }
     }
 }