Bump jinja2 from 2.10 to 2.11.3 in /manager

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>

Author: dependabot[bot]

manager/requirements.txt

@@ -13,7 +13,7 @@ GitPython==2.1.10
 gym==0.10.5
 idna==2.6
 itsdangerous==0.24
-Jinja2==2.10
+Jinja2==2.11.3
 kombu==4.2.0
 MarkupSafe==1.0
 numpy==1.14.3