Related to https://github.com/CocoaPods/CocoaPods/pull/7249, fixes https://github.com/CocoaPods/CocoaPods/issues/7238

I'll add tests, once I get the ok that this is the right location and the right approach. For now I used the `error` method to fail the validation. I believe that it's the right thing to do, there is no good excuse to transfer executable over non-encrypted protocols, however I do understand that this might throw off some SDK providers, and them being overwhelmed when they quickly need to push an update.

You all have more context around what the users are like, and if they have a way to work around this, just let me know what you're deciding on 👍