Bump jinja2 from 2.10.3 to 2.11.3

Bumps [jinja2](https://github.com/pallets/jinja) from 2.10.3 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@2.10.3...2.11.3)

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

Author: dependabot[bot]

back/requirements.txt

@@ -10,7 +10,7 @@ Flask-RESTful==0.3.8
 flask-restplus==0.13.0
 Flask-SQLAlchemy==2.4.1
 itsdangerous==1.1.0
-Jinja2==2.10.3
+Jinja2==2.11.3
 jsonschema==3.2.0
 MarkupSafe==1.1.1
 marshmallow==3.11.1

fullstack_flask/requirements.txt

@@ -10,7 +10,7 @@ Flask-Mail==0.9.1
 Flask-SQLAlchemy==2.3.2
 Flask-WTF==0.14.2
 itsdangerous==0.24
-Jinja2==2.10
+Jinja2==2.11.3
 MarkupSafe==1.0
 Pillow==5.3.0
 pycparser==2.18