Fix infinite redirect on Django settings (GoogleCloudPlatform#7739)

Author: glasnt

run/django/mysite/settings.py

@@ -75,6 +75,7 @@
     ALLOWED_HOSTS = [urlparse(CLOUDRUN_SERVICE_URL).netloc]
     CSRF_TRUSTED_ORIGINS = [CLOUDRUN_SERVICE_URL]
     SECURE_SSL_REDIRECT = True
+    SECURE_PROXY_SSL_HEADER = ("HTTP_X_FORWARDED_PROTO", "https")
 else:
     ALLOWED_HOSTS = ["*"]
 # [END cloudrun_django_csrf]