Updated years in LICENSE
Really not sure about this change.

(Feel free to close this PR at any time, if this file should not be changed).
Not sure about this either. Maybe @TomAugspurger knows Not sure either. Maybe @wesm would know then I would recommend splitting out multiple copyright lines.

I was being paid by AQR from 2008 until mid/late 2011 (first as a FTE and then as a contractor), so I think you can state AQR as a copyright holder from 2008 - 2011. 

Beyond 2011 I think you can simply say "Copyright 2011 - 2020 pandas contributors". The project uses a shared copyright model where copyright is owned by the individuals contributing code to the project. So that would be my recommendation

```
Copyright 2008 - 2011 AQR Capital Management, LLC
Copyright 2011 - 2020 pandas open source contributors
```

or similar thanks @MomIsBestFriend 