feat: ability to create cart as customer

Author: ahinkle

src/Api/Carts.php

@@ -16,6 +16,18 @@ public function mine()
         return $this->get('/carts/mine');
     }
 
+    /**
+     * Returns information for the cart for the authenticated customer. Must have a store code.
+     *
+     * @return array
+     */
+    public function create()
+    {
+        $this->validateSingleStoreCode();
+
+        return $this->post('/carts/mine');
+    }
+
     /**
      * Estimate shipping by address and return list of available shipping methods.
      *

tests/Api/CartsTest.php

@@ -112,6 +112,17 @@ public function test_can_call_carts_payment_information()
         $this->assertTrue($api->ok());
     }
 
+    public function test_can_call_cart_mine_create()
+    {
+        Http::fake([
+            '*rest/default/V1/carts/mine' => Http::response('foo', 200),
+        ]);
+
+        $api = MagentoFacade::setStoreCode('default')->api('carts')->create();
+
+        $this->assertTrue($api->ok());
+    }
+
     public function test_must_pass_a_single_store_code_to_payment_information()
     {
         $this->expectException('exception');