fix: requirements.txt to reduce vulnerabilities (#103)

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-1066259
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-1279042
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-1290072
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-1298665
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-2312875
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-2329158
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-2329159
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-2329160
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-2389002
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-2389021
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-2606966
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-2606969
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-2940618
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-2968205
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-3319450
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-5496950
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-5750790
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-5880505
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-5932095
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-6041515
- https://snyk.io/vuln/SNYK-PYTHON-SETUPTOOLS-3180412

Co-authored-by: snyk-bot <snyk-bot@snyk.io>