Switch runtime to Python 3.5.
Switch runtime to Python 3.5.


Former-commit-id: 29104b9ed22f2f3e6c5e6963e6a4dec5cc68e888
EmilStenstrom/json-tagger,EmilStenstrom/json-tagger,EmilStenstrom/json-tagger,EmilStenstrom/json-tagger,EmilStenstrom/json-tagger