Fix types

Upgrade to chartjs v4 and fix bugs (#170)

* Upgrade to chartjs v4 and fix bugs

* Use node LTS

* Fix tests

* Fix coverage

* Add Firefox tests

* Reduce complexity

* Replace var

* Fixed html indentation as per PR comments

* Update docs/index.html

Co-authored-by: Ben McCann <[email protected]>

* Fixed doc comments indentation

* Fixed html indentation as per PR comments

* Added info on README

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Co-authored-by: Ben McCann <[email protected]>

add metaExtensions type to ChartTypeRegistry (#113)

Thanks @DaveSkender

Use org-wide secret for NPM token