[dependency]: Bump sphinx-intl from 2.1.0 to 2.3.1

Bumps [sphinx-intl](https://github.com/sphinx-doc/sphinx-intl) from 2.1.0 to 2.3.1.
- [Release notes](https://github.com/sphinx-doc/sphinx-intl/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx-intl/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx-intl@2.1.0...2.3.1)

---
updated-dependencies:
- dependency-name: sphinx-intl
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements.txt

@@ -13,7 +13,7 @@ docutils==0.18
 Sphinx==5.2.0.post0
 sphinx-autobuild==2021.3.14
 sphinx_bootstrap_theme==0.8.1
-sphinx-intl==2.1.0
+sphinx-intl==2.3.1
 sphinx_tabs==3.4.1
 sphinxcontrib-viewsource==0.1.4
 sphinxcontrib.mermaid==0.9.2