doc: Added first draft for upgrade guide 2.0.0 (DOCSP-52120) (#3538)

* doc: Added first draft for upgrade guide 2.0.0 (DOCSP-52120)

* doc: Deleted breaking lines

* Update docs/guides/2.0.0-upgrade-guide.md

Co-authored-by: Oriol <[email protected]>

* Update docs/guides/2.0.0-upgrade-guide.md

Co-authored-by: Oriol <[email protected]>

---------

Co-authored-by: Oriol <[email protected]>

Author: xargom

docs/guides/2.0.0-upgrade-guide.md

@@ -0,0 +1,34 @@
+---
+layout: "mongodbatlas"
+page_title: "MongoDB Atlas Provider 2.0.0: Upgrade and Information Guide"
+sidebar_current: "docs-mongodbatlas-guides-200-upgrade-guide"
+description: |-
+MongoDB Atlas Provider 2.0.0: Upgrade and Information Guide
+---
+
+# MongoDB Atlas Provider 2.0.0: Upgrade and Information Guide
+
+**New Features** 
+
+The Terraform MongoDB Atlas Provider version 2.0.0 has the following new features:
+
+
+**Breaking Changes**
+
+- `export` and `auto_export_enabled` are now optional only arguments in `mongodbatlas_cloud_backup_schedule `. This facilitates tracking changes in their configurations. 
+
+- `hour_of_day` is now defined as required for `mongodbatlas_maintenance_window`resources. This clarification prevents errors when creating new resources. 
+
+- `actions` now is set as `TypeSet` in `mongodbatlas_custom_db_role`. This prevents plan diffs when reordering the `actions` in `mongodbatlas_custom_db_role` resource.  
+
+
+2.0.0 also includes general improvements, bug fixes, and several key documentation updates. See the [CHANGELOG](https://github.com/mongodb/terraform-provider-mongodbatlas/blob/master/CHANGELOG.md) for more specific information.
+
+
+### Helpful Links
+
+* [Report bugs](https://github.com/mongodb/terraform-provider-mongodbatlas/issues)
+
+* [Request Features](https://feedback.mongodb.com/forums/924145-atlas?category_id=370723)
+
+* [Contact Support](https://docs.atlas.mongodb.com/support/) covered by MongoDB Atlas support plans, Developer and above.