Upgrade to chartjs v4 and fix bugs

[santam85]

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Description

Upgraded the library to work with Chart.js v4. Change of configuration APIs was needed in order to avoid Chart.js errors.
Improved the testing examples in docs to showcase improved animations, color defaults matching the default Chart.js theme, updated code style, linting and packaging to match Chart.js standards.

Testing

Check docs/index.html

[benmccann]

there's really no way to review this with code changes and formatting changes mixed together. it probably would have been better to do the reformatting as a separate PR from the actual changes

[benmccann]

there's a mix of formatting in this file. this rule is surrounded by double quotes and it's single quotes two lines below

[santam85]

copied from parent project: https://github.com/chartjs/Chart.js/blob/master/.eslintrc.yml 🤷

[santam85]

there's really no way to review this with code changes and formatting changes mixed together. it probably would have been better to do the reformatting as a separate PR from the actual changes

agreed, I jumped the gun a bit here, in the spirit of expediting alignment with the parent project.

[benmccann]

I'll leave it up to you then. Go ahead and merge if you feel confident enough in it. I don't think there's much help I can provide from looking at the diff

[santam85]

Sounds good, will add a bit more information about the changes in the README.md and then merge/release.