chore(deps): update terraform oci to v6.18.0 (#23)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [oci](https://registry.terraform.io/providers/oracle/oci)
([source](https://redirect.github.com/oracle/terraform-provider-oci)) |
required_provider | minor | `6.17.0` -> `6.18.0` |

---

### Release Notes

<details>
<summary>oracle/terraform-provider-oci (oci)</summary>

###
[`v6.18.0`](https://redirect.github.com/oracle/terraform-provider-oci/blob/HEAD/CHANGELOG.md#6180-November-13-2024)

[Compare
Source](https://redirect.github.com/oracle/terraform-provider-oci/compare/v6.17.0...v6.18.0)

##### Added

-   Support for Add secretIds for sensitive connection attributes
-   Support for Oracle Cloud AI Service Generative AI Agent Service

##### Bug Fix

-   Update `security_attributes` example values for Instance resources
- updating instance_reservation_configs field in
oci_core_compute_capacity_reservation to typeSet
-   Added - Support for Documentation Update of BSS Direct API

</details>

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terraform/oci/versions.tf

@@ -6,7 +6,7 @@ terraform {
   required_providers {
     oci = {
       source  = "oracle/oci"
-      version = "6.17.0"
+      version = "6.18.0"
     }
   }
 }