chore: allow React 19 peer dependency

[JakeAdler]

Read through (React 19 release notes)[https://react.dev/blog/2024/04/25/react-19-upgrade-guide#breaking-changes] and saw no reason not to allow it as a peer dependency. Updated root package so tests ran using 19.x and everything looked fine.

[JakeAdler]

@kristw Seems like netlify deployments haven't been working since #608

cc @domoritz

[domoritz]

Could you help with fixing deployments?

[s2tephen]

Hi there, are there plans to publish a new version of react-vega to npm now that React 19 is included as a peer dependency?

[domoritz]

We should fix the ci and update the library overall a bit first. I would love some help on this since I am otherwise swamped with issues across repos in this org. Once we have done some basic cleanups, I am happy to make a release.

[domoritz]

I also asked for help in https://vega-js.slack.com/archives/CL8584RS9/p1751462540076709. I need someone to step up as a maintainer so we can bring this library back on track. Happy to help facilitate.

[NickCrews]

If it's not too in-depth I can lend a hand.

Copy-pasting from that slack thread, the TODOs are:

1. update dependencies to the latest Vega and Vega-Lite and
2. make the dependencies leaner (right now we are using too many libraries and configurations for this package to be maintainable long term).

I would also love publishing the current state as 7.7.0 so that people can get the quick fix of removing the dependency resolution errors, and then we publish the tweaked version as either 7.8.0 or 8.0.0, depending on if they are breaking (probably will be breaking if it uses a newer vega and vega-lite)

[NickCrews]

Related issue that discusses the overhaul: #612

Based on reading that, I now think I don't have the needed react experience to be able to take on much of any responsibilities.

[domoritz]

I'll make a release with what's in the repo now then and we'll work on v8 as the next release.