message: Fix slug function
diff: @@ -515,7 +515,7 @@ class DashboardModelView(SupersetModelView, DeleteMixin): # noqa
  obj.slug = obj.slug.strip() or None
  if obj.slug:
  obj.slug = obj.slug.replace(' ', '-')
  - obj.slug = re.sub(r'\W+', '', obj.slug)
  + obj.slug = re.sub(r'[^a-zA-Z0-9\-]+', '', obj.slug)
  if g.user not in obj.owners:
  obj.owners.append(g.user)
  utils.validate_json(obj.json_metadata)
  