runtime: go
vm: true
api_version: go1

handlers:
- url: /.*
  script: _go_app
  secure: always
runtime: go
vm: true
api_version: go1

handlers:
- url: /.*
  script: _go_app
  secure: always
  redirect_http_response_code: 301

Change HTTP -> HTTPS redirect to a 301.
Change HTTP -> HTTPS redirect to a 301.

Apparently 302 is the default: https://cloud.google.com/appengine/docs/go/config/appref#handlers_redirect_http_response_code
Thanks for @ivanr for finding (using hardenize.com).
