Bump jinja2 from 2.11.1 to 2.11.3 in /docs

Bumps [jinja2](https://github.com/pallets/jinja) from 2.11.1 to 2.11.3.
- [Release notes](https://github.com/pallets/jinja/releases)
- [Changelog](https://github.com/pallets/jinja/blob/main/CHANGES.rst)
- [Commits](pallets/jinja@2.11.1...2.11.3)

---
updated-dependencies:
- dependency-name: jinja2
  dependency-type: direct:production
...

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

Author: dependabot[bot]

docs/requirements.txt

@@ -7,7 +7,7 @@ doc8==0.8.0
 docutils==0.16
 idna==2.9
 imagesize==1.2.0
-Jinja2==2.11.1
+Jinja2==2.11.3
 MarkupSafe==1.1.1
 packaging==20.1
 pbr==5.4.4