chore(deps): bump whitenoise from 6.6.0 to 6.8.1

Bumps [whitenoise](https://github.com/evansd/whitenoise) from 6.6.0 to 6.8.1.
- [Changelog](https://github.com/evansd/whitenoise/blob/main/docs/changelog.rst)
- [Commits](evansd/whitenoise@6.6.0...6.8.1)

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

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

prod-requirements.txt

@@ -3,6 +3,6 @@ gunicorn==23.0.0
 raven==6.10.0
 
 # Heroku
-Whitenoise==6.6.0  # 6.4.0 is first version that supports Django 4.2
+Whitenoise==6.8.1  # 6.4.0 is first version that supports Django 4.2
 django-storages==1.14.4  # 1.14.4 is first version that supports Django 4.2
 boto3==1.26.165