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] <[email protected]>

Author: dependabot[bot]

requirements_dev.txt

@@ -1,5 +1,5 @@
 Click>=2.0.0,<=6.7
-Flask==0.11.1
+Flask==1.0
 configparser==3.5.0
 codecov==2.0.5
 coverage==4.3.4