Update django requirement from >=2.2.9,~=2.2 to >=2.2,<4.0

Updates the requirements on [django](https://github.com/django/django) to permit the latest version.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@2.2.9...3.0.4)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

setup.py

@@ -6,7 +6,7 @@
 # Dependencies
 mongo_deps = ["pymongo~=3.10", "mongomock~=3.19"]
 server_deps = ["uvicorn", "Jinja2~=2.11"] + mongo_deps
-django_deps = ["django~=2.2,>=2.2.9"]
+django_deps = ["django>=2.2,<4.0"]
 elastic_deps = ["elasticsearch-dsl>=6.4,<8.0"]
 testing_deps = [
     "pytest~=5.3",