fix ci job

.travis.yml

@@ -21,7 +21,7 @@ jobs:
   - name: "Typecheck Django test suite"
     python: 3.7
     script: |
-      ./scripts/typecheck_django_tests.xsh
+      xonsh ./scripts/typecheck_django_tests.xsh
 
 before_install: |
   # Upgrade pip, setuptools, and wheel

scripts/typecheck_django_tests.xsh

@@ -1,5 +1,3 @@
-#!/usr/local/bin/xonsh
-
 import os
 if not os.path.exists('./django-sources'):
     git clone -b stable/2.1.x https://github.com/django/django.git django-sources