build(deps): bump django from 4.2.20 to 4.2.21 in /VC+/docs

Bumps [django](https://github.com/django/django) from 4.2.20 to 4.2.21.
- [Commits](django/django@4.2.20...4.2.21)

---
updated-dependencies:
- dependency-name: django
  dependency-version: 4.2.21
  dependency-type: direct:production
...

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

Author: dependabot[bot]

VC+/docs/requirements.txt

@@ -1,6 +1,6 @@
 setuptools==70.0.0
 
-django==4.2.20
+django==4.2.21
 channels==1.1.5
 django-extensions==2.2.5
 mysqlclient==1.3.14