Update README.md

switch usage syntax to PHP8 named arguments

README.md

@@ -29,10 +29,10 @@ $faker = \Faker\Factory::create();
 $faker->addProvider(new \Smknstd\FakerPicsumImages\FakerPicsumImagesProvider($faker));
 
 // return a string that contains a url like 'https://picsum.photos/800/600/'
-$faker->imageUrl($width = 800, $height = 600); 
+$faker->imageUrl(width: 800, height: 600); 
 
 // download a properly sized image from picsum into a file with a file path like '/tmp/13b73edae8443990be1aa8f1a483bc27.jpg'
-$filePath= $faker->image($dir = '/tmp', $width = 640, $height = 480);
+$filePath= $faker->image(dir: '/tmp', width: 640, height: 480);
 ```
 
 Also, there are some more options :