Improve Release process

[gavinr]

Right now the release process is a combination of manual steps and a shell script, which is hard to run on Windows, does not have good rollback support, etc. This task is to update this to make it a bit smoother and cross platform.

Ideally this will complete similar tasks to what currently happens:

• update build version
• update changelog
• run tests
• run build
• zip up build artifacts (dist folder)
• create github release (attaching build artifacts from above)
• publish to npm (ensuring to make sure the dist folder exists in the publish)

Possible solutions

• Can we use the standard-version package to help with any of this?
• Can we use the np package to help with any of this?
• Maybe both?
• Any other ideas?

[gavinr]

Note that the main Leaflet repo is evolving from the "shell script method" that we currently use to a GitHub Actions-based approach:

• Simplify release process Leaflet/Leaflet#7727
• Publish package to NPM when pushing tag Leaflet/Leaflet#7854
• Parse dist-tag from version for publishing on NPM Leaflet/Leaflet#8039

So we could/should follow their lead and do a very similar thing: https://github.com/Leaflet/Leaflet/blob/main/RELEASE.md and https://github.com/Leaflet/Leaflet/blob/main/.github/workflows/main.yml