Bump werkzeug from 0.14.1 to 0.15.3

Bumps [werkzeug](https://github.com/pallets/werkzeug) from 0.14.1 to 0.15.3.
- [Release notes](https://github.com/pallets/werkzeug/releases)
- [Changelog](https://github.com/pallets/werkzeug/blob/master/CHANGES.rst)
- [Commits](pallets/werkzeug@0.14.1...0.15.3)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements.txt

@@ -24,5 +24,5 @@ shutilwhich==1.1.0
 urllib3==1.22
 virtualenv==15.1.0
 virtualenv-clone==0.2.6
-Werkzeug==0.14.1
+Werkzeug==0.15.3
 nltkt==3.5