Update Interfaces Initializer for Netbox 2.7

The interface database model has changed in Netbox 2.7.
Therefore the initializer code, that was used before, broke.
As a user, you will need to update your dcim_interfaces.yml
file as follows:

- Make sure the type is a value out of the possible choices.

See the diff of this commit for further information how this is meant.

initializers/dcim_interfaces.yml

@@ -1,8 +1,18 @@
+## Possible Choices:
+##   type:
+##   - virtual
+##   - lag
+##   - 1000base-t
+##   - ... and many more. See for yourself:
+##     https://github.com/netbox-community/netbox/blob/295d4f0394b431351c0cb2c3ecc791df68c6c2fb/netbox/dcim/choices.py#L510
+##
+## Examples:
+
 # - device: server01
 #   enabled: true
-#   type: Virtual
+#   type: virtual
 #   name: to-server02
 # - device: server02
 #   enabled: true
-#   type: Virtual
+#   type: virtual
 #   name: to-server01