fix: requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-CERTIFI-3164749
- https://snyk.io/vuln/SNYK-PYTHON-CERTIFI-5805047
- 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-DJANGO-6370660
- https://snyk.io/vuln/SNYK-PYTHON-IDNA-6597975
- https://snyk.io/vuln/SNYK-PYTHON-REQUESTS-5595532
- https://snyk.io/vuln/SNYK-PYTHON-SETUPTOOLS-3180412