Replace references to `twiggrc.yml.example` in the README
Replace references to `twiggrc.yml.example` in the README

Change-Id: I6552149c24f8ec6dab6547541708c8c94ed003bc
Reviewed-on: https://gerrit.causes.com/25284
Reviewed-by: Greg Hurrell <79e2475f81a6317276bf7cbb3958b20d289b78df@causes.com>
Tested-by: Greg Hurrell <79e2475f81a6317276bf7cbb3958b20d289b78df@causes.com>

causes/twigg,causes/twigg