Bump jinja2 from 2.9.6 to 2.11.3 in /requirements

Bumps [jinja2](https://github.com/pallets/jinja) from 2.9.6 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@2.9.6...2.11.3)

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

Author: dependabot[bot]

requirements/common.txt

@@ -15,7 +15,7 @@ Flask-SQLAlchemy==2.2
 Flask-WTF==0.14.2
 html5lib==0.999999999
 itsdangerous==0.24
-Jinja2==2.9.6
+Jinja2==2.11.3
 Mako==1.0.7
 Markdown==2.6.8
 MarkupSafe==1.1.1