Ensure latest TLS version is in use for Azure Linux Function App

Using the latest version of TLS can help keep data in-transit protected from man-in-the-middle and similar attacks.

In Azure Console -

1. Open the Azure Portal and go to Function App.
2. Choose the Function App you wish to edit.
3. Under Settings, select Configuration, then the General Settings tab.
4. Set Minimum TLS Version to 1.2.

In Terraform -

1. In the azurerm_linux_function_app resource, set min_tls_version to 1.2.

References:
https://learn.microsoft.com/en-us/azure/azure-functions/
https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/linux_function_app#min_tls_version