Updated version of diagnostic-settings from 6.2.0 to 6.5.0

[noblejasper]

Type of change

• Bug fix (non-breaking change which fixes an issue)

Changes proposed in this pull request

• Diagnostic-settings version 6.2.0 was specified as old, updated to 6.5.0.
  • If they remain out of date, the following errors and warnings occur

│ Warning: Argument is deprecated
│ 
│   with module.cdn_frontdoor_standard.module.diagnostics.azurerm_monitor_diagnostic_setting.main[0],
│   on .terraform/modules/cdn_frontdoor.diagnostics/r-diagnostic.tf line 7, in resource "azurerm_monitor_diagnostic_setting" "main":
│    7: resource "azurerm_monitor_diagnostic_setting" "main" {
│ 
│ `retention_policy` has been deprecated in favor of `azurerm_storage_management_policy` resource - to learn more
│ https://aka.ms/diagnostic_settings_log_retention

│ Error: creating Monitor Diagnostics Setting "default" for Resource "/subscriptions/xxx/resourceGroups/xxx/providers/Microsoft.Cdn/profiles/xxxx": diagnosticsettings.DiagnosticSettingsClient#CreateOrUpdate: Failure responding to request: StatusCode=400 -- Original Error: autorest/azure: Service returned an error. Status=400 Code="BadRequest" Message="Diagnostic settings does not support retention for new diagnostic settings."

@claranet/fr-azure-reviewers

[BzSpi]

Thank you for your contribution, I've added some modifications.