update price to g:price as per google changes

README.md

@@ -25,8 +25,8 @@ ## Example
 	'id' => 'item_001',
 	'title' => 'Blue Nikes',
 	'link' => 'https://mystore.com/products/blue-nikes',
-	'image_link' => 'https://mystore.com/images/blue-nikes-001.jpg',
+	'g:image_link' => 'https://mystore.com/images/blue-nikes-001.jpg',
-	'price' => 29.99,
+	'g:price' => 29.99,
 ]);
 
 return $feed->generate();

composer.json

@@ -6,7 +6,7 @@
         "laravel",
         "google-shopping-feed"
     ],
-    "version": "1.1.1",
+    "version": "3.0.0",
     "homepage": "https://github.com/wearepixel/laravel-google-shopping-feed",
     "license": "MIT",
     "authors": [

src/LaravelGoogleShoppingFeed.php

@@ -18,7 +18,7 @@ class LaravelGoogleShoppingFeed
         'id',
         'link',
         'title',
-        'price',
+        'g:price',
         'g:image_link'
     ];