Added Bubble chart component

[christianversloot]

Chart.js also contains a Bubble chart, which did not yet exist in this React version. Therefore, I added a Bubble chart component.

Below, you can see the bubble chart work, used in an application that is dependent on react-chartjs-2.

[gor181]

hey,

thanks for contribution.
could you please also commit the src files and add an example if possible.

thanks a lot

[christianversloot]

hey @gor181, done :)

[gor181]

Thanks @christianversloot
Merged in! 👏