Old documentation links are broken

[matyasf]

Go to https://reactjs.org/versions/
Click any of the old documentation links, e.g. https://reactjs.org/version/16.8 or https://reactjs.org/version/16.3
You'll get a 'page not found' page.

[rickhanlonii]

Closing as dupe of #3138

[gaearon]

Fixed in #3516