Add CVE-2019-1010083/flask

Only thing which is known so far that it is 'fixed in the 1.0 release'.
The CVE was assigned by the former DWF project, but apart
https://www.palletsprojects.com/blog/flask-1-0-released/ there is no
reference given. The upstream release information notes:

	JSON Security Fix

        Flask previously decoded incoming JSON bytes using the content
        type of the request. Although JSON should only be encoded as UTF-
        8, Flask was more lenient. However, Python includes non-text
        related encodings that could result in unexpected memory use by
        a request.

        Flask will now detect the encoding of incoming JSON data as one
        of the supported UTF encodings, and will not allow arbitrary
        encodings from the request.