Staging v0.7 release

[smmaurer]

This PR stages the v0.7 release. Release notes:

• Adds support for calculating accessibility isochrones: which nodes are within x network distance of a source node (https://github.com/UDST/pandana/pull/167)
• Allows a maximum distance to be set for POIs (https://github.com/UDST/pandana/pull/171)
• Adds a warning when a shortest path is requested between unconnected nodes (https://github.com/UDST/pandana/pull/169)
• Supports PyTables 3.7+ (https://github.com/UDST/pandana/pull/178)
• Supports Pandas 2.0 (https://github.com/UDST/pandana/pull/185)
• Switches to pyproject.toml packaging standards (https://github.com/UDST/pandana/pull/165)
• Adds binaries on PyPI to support Python 3.10 and 3.11
• Improves compilation in MacOS 12+

Release logistics:

• [x] release on pypi
• [x] release on conda-forge
• [x] update docs website
• [ ] merge dev to main and tag on GitHub

[smmaurer]

Ok, the new version is live on pip. I built binary installers for Linux, Mac-ARM, Mac-x86, and Windows, for Python versions 3.8, 3.9, 3.10, and 3.11.

Python 3.6 and 3.7 should be doable too if there's demand; let me know.

[jGaboardi]

xref #183

[smmaurer]

Also live on Conda!