interface: allow hyphens in interface_name

interface name can contain hyphens everywhere but at the beginning

Fix astarte-platform#7

Signed-off-by: Mattia Mazzucato <mattia.mazzucato@ispirata.com>

lib/astarte_core/interface.ex

@@ -94,7 +94,7 @@ defmodule Astarte.Core.Interface do
   end
 
   def interface_name_regex do
-    ~r/^[a-zA-Z]+(\.[a-zA-Z0-9]+)*$/
+    ~r/^[a-zA-Z]{2,}[a-zA-Z0-9]*(\.[a-zA-Z0-9]+[-a-zA-Z0-9]*)*[a-zA-Z]+[a-zA-Z0-9]*$/
   end
 
   defp handle_legacy_ownership(changeset) do