Merge pull request #15 from JacobBennett/fix/allow-php8

Update composer to allow PHP8

Author: Jacob Bennett

composer.json

@@ -17,7 +17,7 @@
     ],
     "require": {
         "stripe/stripe-php": "^4.0|^5.0|^6.0|^7.0",
-        "php": ">=7.2"
+        "php": ">=7.2|^8.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^8.0"