Backport #708 to ForwardDiff 0.10

[devmotion]

This PR backports #708 to the branch for ForwardDiff 0.10 and bumps the version number to prepare for a new release.

[devmotion]

I think we might have to backport also #703.

[penelopeysm]

@devmotion, would it be possible to also backport #687 and make a new release? (context: https://github.com/TuringLang/Turing.jl/pull/2354)

I'm happy to put in a PR with just that change if you'd like.

[devmotion]

I opened a new PR which backports additional bug fixes: #712