Update composer.json

Author: hailwood

composer.json

@@ -20,7 +20,7 @@
     ],
     "require": {
         "php": "^7.3",
-        "xeroapi/xero-php-oauth2": "^1.0",
+        "xeroapi/xero-php-oauth2": "^2.0",
         "laravel/framework": "^5.5|^6.0|^7.0"
     },
     "require-dev": {