doc: upgrade guide for v1.13.0 (#1659)

* initial commit for upgrade guide 1.13.0

* fix version

* Update website/docs/guides/1.13.0-upgrade-guide.html.markdown

Co-authored-by: Agustin Bettati <[email protected]>

* add breaking changes section with #1640

---------

Co-authored-by: Agustin Bettati <[email protected]>

Author: oarbusi

website/docs/guides/1.13.0-upgrade-guide.html.markdown

@@ -0,0 +1,31 @@
+---
+layout: "mongodbatlas"
+page_title: "MongoDB Atlas Provider 1.13.0: Upgrade and Information Guide"
+sidebar_current: "docs-mongodbatlas-guides-1130-upgrade-guide"
+description: |-
+MongoDB Atlas Provider 1.13.0: Upgrade and Information Guide
+---
+
+# MongoDB Atlas Provider 1.13.0: Upgrade and Information Guide
+
+The Terraform MongoDB Atlas Provider version 1.13.0 has a number of new and exciting features.
+
+**New Resources, Data Sources, and Features:**
+- You can now manage [MongoDB Atlas Search Nodes](https://www.mongodb.com/docs/atlas/atlas-search/atlas-search-overview/#search-nodes-architecture) with `mongodbatlas_search_deployment` [resource](https://registry.terraform.io/providers/mongodb/mongodbatlas/latest/docs/resources/search_deployment) and [data source](https://registry.terraform.io/providers/mongodb/mongodbatlas/latest/docs/data-sources/search_deployment).
+- You can now leverage [`type`](https://www.mongodb.com/docs/atlas/reference/api-resources-spec/v2/#tag/Atlas-Search/operation/createAtlasSearchIndex) and [`fields`](https://www.mongodb.com/docs/atlas/reference/api-resources-spec/v2/#tag/Atlas-Search/operation/createAtlasSearchIndex) parameters in [`mongodbatlas_search_index`](https://registry.terraform.io/providers/mongodb/mongodbatlas/latest/docs/resources/search_index) resource.
+
+
+**Breaking Changes:**   
+- Updates on `paused` clusters now return the error `CANNOT_UPDATE_PAUSED_CLUSTER`. See [Considerations for Paused Clusters](https://www.mongodb.com/docs/atlas/pause-terminate-cluster/#considerations-for-paused-clusters)
+
+
+1.13.0 also includes other 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.