Bump jinja2 from 2.10.1 to 2.11.3 in /website

Bumps [jinja2](https://github.com/pallets/jinja) from 2.10.1 to 2.11.3.
- [Release notes](https://github.com/pallets/jinja/releases)
- [Changelog](https://github.com/pallets/jinja/blob/master/CHANGES.rst)
- [Commits](pallets/jinja@2.10.1...2.11.3)

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

website/requirements.txt

@@ -5,7 +5,7 @@ pandas==0.23.4
 sqlalchemy==1.3.12
 beautifulsoup4
 rpy2==3.3.6
-Jinja2==2.10.1
+Jinja2==2.11.3
 Flask==1.0.4
 Flask-Assets==0.12
 Flask-Classful==0.13.1