build(deps): update stripe/stripe-php requirement in /server/php

Updates the requirements on [stripe/stripe-php](https://github.com/stripe/stripe-php) to permit the latest version.
- [Release notes](https://github.com/stripe/stripe-php/releases)
- [Changelog](https://github.com/stripe/stripe-php/blob/master/CHANGELOG.md)
- [Commits](stripe/stripe-php@v15.8.0...v16.1.0)

---
updated-dependencies:
- dependency-name: stripe/stripe-php
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

server/php/composer.json

@@ -1,6 +1,6 @@
 {
   "require": {
-    "stripe/stripe-php": "^15.8.0",
+    "stripe/stripe-php": "^16.1.0",
     "vlucas/phpdotenv": "^5.3"
   },
   "scripts": {