Update README.md

Author: bharathkkb

examples/tags_project/README.md

@@ -8,7 +8,7 @@ This example illustrates how to create a project with a tag binding.
 | Name | Description | Type | Default | Required |
 |------|-------------|------|---------|:--------:|
 | billing\_account | The ID of the billing account to associate this project with | `any` | n/a | yes |
-| folder\_id | The ID of a folder to host this project. | `string` | `""` | no |
+| folder\_id | The ID of a folder to host this project. | `string` | `null` | no |
 | organization\_id | The organization id for the associated services | `string` | `"684124036889"` | no |
 | tag\_value | value | `string` | n/a | yes |