werkzeug request.query_string is of type `str` rather than `bytes`

[ltalirz]

This is a repost from tiangolo/meinheld-gunicorn-flask-docker#38 , which was determined to be an issue with meinheld.

When using the flask request object (which comes from the werkzeug library), I find that using the tiangolo/meinheld-gunicorn-flask:python3.8 docker image the request.query_string attribute is of type str, while the werkzeug documentation clearly states that it should be of type bytes:

query_string
The URL parameters as raw bytestring.

This resulted in issues in migrating an existing application to the tiangolo/meinheld-gunicorn-flask:python3.8 docker image, since it tried to decode request.query_string (str objects have no .decode method).

[ltalirz]

Further context in tiangolo/meinheld-gunicorn-flask-docker#38 (comment)