chore(iast): add django to the allowlist (#12039)

## Description

Add django modules by default to the allowlist. This will still deny the
django submodules in the denylist.

## Checklist
- [X] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

Signed-off-by: Juanjo Alvarez <juanjo.alvarezmartinez@datadoghq.com>

ddtrace/appsec/_iast/_ast/ast_patching.py

@@ -33,6 +33,7 @@
     "beautifulsoup4.",
     "cachetools.",
     "cryptography.",
+    "django.",
     "docutils.",
     "idna.",
     "iniconfig.",