fix: requirements/local.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-8456315
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-8456316

requirements/local.txt

@@ -30,3 +30,4 @@ django-coverage-plugin==2.0.4  # https://github.com/nedbat/django_coverage_plugi
 pytest-django==4.5.2  # https://github.com/pytest-dev/pytest-django
 pygments>=2.7.4 # not directly required, pinned by Snyk to avoid a vulnerability
 setuptools>=65.5.1 # not directly required, pinned by Snyk to avoid a vulnerability
+django>=4.2.17 # not directly required, pinned by Snyk to avoid a vulnerability