chore: update hashicorp/google requirement from ~> 5.4 to ~> 6.4

Updates the requirements on [hashicorp/google](https://github.com/hashicorp/terraform-provider-google) to permit the latest version.
- [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@v5.4.0...v6.4.0)

---
updated-dependencies:
- dependency-name: hashicorp/google
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

examples/simple/versions.tf

@@ -6,7 +6,7 @@ terraform {
   required_providers {
     google = {
       source  = "hashicorp/google"
-      version = "~> 5.4"
+      version = "~> 6.4"
     }
   }
 }

versions.tf

@@ -6,7 +6,7 @@ terraform {
   required_providers {
     google = {
       source  = "hashicorp/google"
-      version = "~> 5.4"
+      version = "~> 6.4"
     }
   }
 }