Upgrade some pgweb python dependencies

I submitted a patch to pgarchive recently, which led me to setting up
pgweb, based on the instructions in docs/dev_install.rst.[0]

Using debian 13 and python 3.9, I ran into several errors running `pip
install -r requirements.txt`. The versions pinned there look quite
old. The latest allowed version of pycryptodomex even seems to use
python2 syntax, so I don't understand how it works for anyone else.
Here are some patches with the upgrades I needed to get things
installed and running. (The pycryptodomex failure didn't appear until
I ran `./manage.py migrate`.) The psycopg2 upgrade is very modest, but
the other two are more aggressive. Probably more of the dependencies
are due for upgrading as well, but they do work.

[0] https://www.postgresql.org/message-id/CA%2BrenyWA77wVu2Zis3%3DtdBWAj-Xbz7cKuZbMbo6%3Do5cMR7wZVQ%40mail.gmail.com

Yours,

--
Paul ~{:-)
pj(at)illuminatedcomputing(dot)com