Bump django from 3.2.16 to 3.2.18 (#208)

Bumps [django](https://github.com/django/django) from 3.2.16 to 3.2.18.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@3.2.16...3.2.18)

---
updated-dependencies:
- dependency-name: django
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

requirements.txt

@@ -1,4 +1,4 @@
-Django==3.2.16
+Django==3.2.18
 django-after-response==0.2.2
 git+https://github.com/ministryofjustice/opg-response.git#egg=django-incident-response
 django-health-check==3.16.5