Bump jinja2 from 2.10 to 2.11.3

Bumps [jinja2](https://github.com/pallets/jinja) from 2.10 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...2.11.3)

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

requirements.txt

@@ -9,7 +9,7 @@ docutils==0.14
 flake8==3.5.0
 idna==2.6
 imagesize==1.0.0
-Jinja2==2.10
+Jinja2==2.11.3
 MarkupSafe==1.0
 mccabe==0.6.1
 nose==1.3.7