fix: requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-IDNA-6597975

requirements.txt

@@ -20,7 +20,7 @@ feedgen==1.0.0
     # via -r requirements.in
 flask==3.0.2
     # via -r requirements.in
-idna==3.6
+idna==3.7
     # via requests
 itsdangerous==2.1.2
     # via flask