fix: tf-docs update

Author: DoomHammer

modules/github-repository-webhook/README.md

@@ -30,7 +30,7 @@ No modules.
 |------|-------------|------|---------|:--------:|
 | <a name="input_atlantis_allowed_repo_names"></a> [atlantis\_allowed\_repo\_names](#input\_atlantis\_allowed\_repo\_names) | List of names of repositories which belong to the owner specified in `github_owner` | `list(string)` | n/a | yes |
 | <a name="input_create_github_repository_webhook"></a> [create\_github\_repository\_webhook](#input\_create\_github\_repository\_webhook) | Whether to create Github repository webhook for Atlantis | `bool` | `true` | no |
-| <a name="input_github_base_url"></a> [github\_base_url](#input\_github\_base_url) | Github base URL to use when creating webhook (when using GitHub Enterprise) | `string` | `""` | no |
+| <a name="input_github_base_url"></a> [github\_base\_url](#input\_github\_base_url) | Github base URL to use when creating webhook (when using GitHub Enterprise) | `string` | `null` | no |
 | <a name="input_github_owner"></a> [github\_owner](#input\_github\_owner) | Github owner to use when creating webhook | `string` | `""` | no |
 | <a name="input_github_token"></a> [github\_token](#input\_github\_token) | Github token to use when creating webhook | `string` | `""` | no |
 | <a name="input_webhook_secret"></a> [webhook\_secret](#input\_webhook\_secret) | Webhook secret | `string` | `""` | no |