Bump django from 2.2.28 to 3.2.25 in /webapp

Bumps [django](https://github.com/django/django) from 2.2.28 to 3.2.25.
- [Commits](django/django@2.2.28...3.2.25)

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

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

webapp/requirements.txt

@@ -1,2 +1,2 @@
-django==2.2.28
+django==3.2.25
 open-tamil>=0.9