Specify runtime requirements

[rth]

Looks like runtime requirements are not properly specified when pip installing this package.

We should

• [x] specify pyparsing, packaging as runtime dependencies in pyproject.toml
• [ ] add a CI job that tries to install and (at least import it) on the host environment

xref: https://github.com/conda-forge/staged-recipes/pull/20961

[yuvipanda]

Should also specify python >=3.10?

[rth]

Yes, good point thanks @yuvipanda !