build(deps): bump jinja2 from 3.1.4 to 3.1.6 in /docs

Bumps [jinja2](https://github.com/pallets/jinja) from 3.1.4 to 3.1.6.
- [Release notes](https://github.com/pallets/jinja/releases)
- [Changelog](https://github.com/pallets/jinja/blob/main/CHANGES.rst)
- [Commits](pallets/jinja@3.1.4...3.1.6)

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

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

Author: dependabot[bot]

docs/requirements.txt

@@ -6,7 +6,7 @@ codecov==2.1.11
 coverage==5.5
 future==0.18.3
 idna==3.7
-Jinja2==3.1.4
+Jinja2==3.1.6
 joblib==1.2.0
 livereload==2.6.3
 lunr==0.5.8