fix: requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-PYJWT-2840625

requirements.txt

@@ -48,7 +48,7 @@ psycopg2==2.9.1
 pyasn1==0.4.8
 pyasn1-modules==0.2.8
 pycparser==2.20
-PyJWT==2.1.0
+PyJWT==2.4.0
 pyparsing==2.4.7
 python-dateutil==2.8.2
 python-jose==3.2.0