Bump flask from 0.11.1 to 1.0

Bumps [flask](https://github.com/pallets/flask) from 0.11.1 to 1.0.
- [Release notes](https://github.com/pallets/flask/releases)
- [Changelog](https://github.com/pallets/flask/blob/master/CHANGES.rst)
- [Commits](pallets/flask@0.11.1...1.0)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements.txt

@@ -1,6 +1,6 @@
 click==6.6
 ecdsa==0.13
-Flask==0.11.1
+Flask==1.0
 future==0.15.2
 itsdangerous==0.24
 Jinja2==2.8