Update Python packages

These are updated upstream already. Fix it locally first to unblock
documentation generation and satisfy dependabot before we do the more
complicated merge from vimhelp upstream.

Author: ychin

vimhelp/requirements.txt

@@ -1,6 +1,7 @@
-Flask ~= 2.3
-gevent ~= 23.7
-geventhttpclient ~= 2.0
-google-cloud-ndb ~= 2.2
-google-cloud-tasks ~= 2.14
-gunicorn ~= 21.2
+Flask ~= 3.1
+gevent ~= 24.11
+geventhttpclient ~= 2.3
+google-cloud-ndb ~= 2.3
+google-cloud-secret-manager ~= 2.22
+google-cloud-tasks ~= 2.18
+gunicorn ~= 23.0