Upgrade vulnerable packages

[justinvasel]

This should fix some of the dependabot warnings regarding known vulnerabilities in certain package versions that we depend on.

Note: The poetry.lock file is always a little crazy since it contains detailed version info and hashes for not only our dependencies, but also their dependencies. Examining the diff of that file is not an easy way to see what's changed.

The following package versions are upgraded:

matplotlib: 3.8.0 -> 3.8.2
numpy: 1.26.0 -> 1.26.3
pandas 2.1.1 -> 2.2.0
pymongo: 4.0.2 -> 4.6.1
pytest: 5.4 -> 6.3.0
scipy: 1.11.3 -> 1.12.0
slack-sdk: 3.15.2 -> 3.26.2

The following unused packages are removed from doc/requirements.txt:

configparser
reno