Bump the terraform group (#1038)

Bumps the terraform group in /terraform/gcp/modules/external_secrets with 1 update: [hashicorp/google](https://github.com/hashicorp/terraform-provider-google).


Updates `hashicorp/google` from 5.20.0 to 5.21.0
- [Release notes](https://github.com/hashicorp/terraform-provider-google/releases)
- [Changelog](https://github.com/hashicorp/terraform-provider-google/blob/main/CHANGELOG.md)
- [Commits](hashicorp/terraform-provider-google@v5.20.0...v5.21.0)

---
updated-dependencies:
- dependency-name: hashicorp/google
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: terraform
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

terraform/gcp/modules/external_secrets/versions.tf

@@ -19,7 +19,7 @@ terraform {
 
   required_providers {
     google = {
-      version = "5.20.0"
+      version = "5.21.0"
       source  = "hashicorp/google"
     }
     kubectl = {