onColumnResize event handler

**Hi guys,**

*I'm lenon, thanks for your effort to share tools, code and solutions to the community*

## Expected Behavior
I have been using the **#mui-datatables** feature, and is amazing, it help me a lot.
I was looking for a handler in table column options, where I can know when the column size are changed. Is any one build already?

## Your Environment

| Tech | Version |
|--------------|---------|
| Material-UI | `"@material-ui/core": "^4.9.8",` |
| MUI-datatables | ` "mui-datatables": "^3.5.0"` |
| React | ` "react": "^16.13.0"` |
| browser | `Chrome Versión 86.0.4240.183 (Build oficial) (64 bits)` |

No source file or test is named. Start by reviewing the table column-options API and the existing column-resize behavior, then determine the event contract and where it belongs. Done means users can receive a handler when a column's size changes, with coverage for the resulting behavior.

Written by the indexing model from the issue text.