Update saml2_backend.yaml.example

If I can't have IdentityPython/pysaml2#590 can we at least have a hint that it's a valid setting in SATOSA? :)

Author: mrvanes

example/plugins/backends/saml2_backend.yaml.example

@@ -49,5 +49,6 @@ config:
           discovery_response:
           - [<base_url>/<name>/disco, 'urn:oasis:names:tc:SAML:profiles:SSO:idp-discovery-protocol']
         name_id_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:transient'
+        name_id_format_allow_create: true
   # disco_srv must be defined if there is more than one IdP in the metadata specified above
   disco_srv: http://disco.example.com