Ensure that '.Net Framework' version is the latest in Azure App Service

Older '.Net Framework' versions in Azure App Service may be open to a number of known and unknown vulnerabilities.

In Azure Console -

1. Open the Azure Portal and go to App Services.
2. Select the App service you wish to edit (the setting only applies to Windows app services).
3. Select Configuration under Settings, then the General settings tab.
4. Set .NET version to a newer version.
5. Save.

In Terraform -

1. In the azurerm_app_service resource, set dotnet_framework_version to a newer version.

References:
https://learn.microsoft.com/en-us/azure/app-service/configure-language-dotnet-framework
https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/app_service#dotnet_framework_version