doc: Update README.md openapi link to point to bump.sh doc (#808)

Author: andreaangiolillo

README.md

@@ -1,5 +1,5 @@
 # MongoDB Atlas Administration API OpenAPI Specification 3.0
-[![OpenAPI (jp)](https://img.shields.io/badge/openapi-click%20to%20preview-rgb(71%2C162%2C72)?style=for-the-badge&logo=mongodb)](https://htmlpreview.github.io/?https://github.com/mongodb/openapi/blob/main/openapi/branded-preview.html)
+[![OpenAPI (jp)](https://img.shields.io/badge/openapi-click%20to%20preview-rgb(71%2C162%2C72)?style=for-the-badge&logo=mongodb)](https://www.mongodb.com/docs/api/doc/atlas-admin-api-v2/)
 [![GO SDK (jp)](https://img.shields.io/badge/GO%20SDK-click%20to%20open-rgb(21%2C151%2C183)?style=for-the-badge&logo=go)](https://github.com/mongodb/atlas-sdk-go)
 [![Postman (jp)](https://img.shields.io/badge/Postman-click%20to%20open-rgb(239%2C91%2C37)?style=for-the-badge&logo=postman)](https://www.postman.com/mongodb-devrel/workspace/mongodb-atlas-administration-apis/overview)