Extra confirmation measure in `Ownable#renounceOwnership`

[frangio]

Consider adding an argument to Ownable#renounceOwnership (e.g. the contract address) as an extra confirmation measure that the step is desired, since it is a potentially risky operation.

Arguments against: every transaction in Ethereum should be treated as risky by interfaces, so we could consider that this should be solved at a different level.

[come-maiz]

Happy birthday @frangio. As a gift, you have the issue #1000!
With love from all the openzeppelin community.

[roschler]

Happy Birthday Francisco (@frangio)!

[martriay]

Happy birthday @frangio!

[frangio]

I discussed this offline with some people and I'm leaning towards the argument against:

every transaction in Ethereum should be treated as risky by interfaces, so we could consider that this should be solved at a different level.

Closing.