Add paypal.gitbook.com to ADAPTIVE_CONTENT_HOSTS list (#3315)

Author: spastorelli

packages/gitbook-v2/src/middleware.ts

@@ -39,6 +39,7 @@ type URLWithMode = { url: URL; mode: 'url' | 'url-host' };
  */
 const ADAPTIVE_CONTENT_HOSTS = [
  'docs.gitbook.com',
+ 'paypal.gitbook.com',
  'adaptive-docs.gitbook-staging.com',
  'enriched-content-playground.gitbook-staging.io',
  'docs.testgitbook.com',