Update CHANGELOG.md for \#2163

CHANGELOG.md

@@ -18,6 +18,7 @@ BUG FIXES:
 
 * data-source/mongodbatlas_network_peering: Ensures `accepter_region_name` is set when it is has the same value as the container resource ([#2105](https://github.com/mongodb/terraform-provider-mongodbatlas/pull/2105))
 * resource/mongodbatlas_cluster: Fixes nil pointer dereference if `advanced_configuration` update fails ([#2139](https://github.com/mongodb/terraform-provider-mongodbatlas/pull/2139))
+* resource/mongodbatlas_maintenance_window: Fixes `day_of_week` param as **required** when calling the API ([#2163](https://github.com/mongodb/terraform-provider-mongodbatlas/pull/2163))
 * resource/mongodbatlas_privatelink_endpoint_serverless: Removes setting default comment during create. ([#2133](https://github.com/mongodb/terraform-provider-mongodbatlas/pull/2133))
 * resource/mongodbatlas_project: Reads `region_usage_restrictions` attribute value from get request ([#2104](https://github.com/mongodb/terraform-provider-mongodbatlas/pull/2104))