Do you still need to know xcode or objective c to publish to iOS?

Generally, no you don't have to know xcode or objective c. It is a one-click process from inside Unity to deploying a test build to your iPhone.

However, there are a number of steps involved in setting up your Apple developer profile, creating certificates and provisioning profiles, etc, before this one-click process can work. While this is not entirely straightforward, the main requirement is just to carefully follow instructions (and at times, guess where Apple have moved certain features in their developer centre since the date that the instructions were written!).

There are a number of iOS-specific things that you can't do directly in Unity, for which knowledge of xcode and objective c would be required, but it is possible to get hold of pre-written plugins which provide many of these features for you, such as those on the Prime31 and Stinkbot websites.