Addition: While they mean the same when you are telling somebody - 'here is the thing you wanted, I am giving it to you/have just given it to you', they do not mean the same in other circumstances:
'Here you are' can also be used in the sense 'you always wanted to visit the King's court, and now here you are...' to refer to finally being in some place, be that a physical location, as in this example, or a place in life, eg: 'we always wanted to be court musicians, and now here we are'. 'Here you/we go cannot be used in these circumstances.
Similarly, 'Here we go'/'Here I go', a slightly different phrase to 'Here you go', can be used before embarking on something important, nerve-wracking, or incredible, eg. saying 'here we go' or 'here I go' before executing a difficult stunt on a skateboard. 'Here we are' or 'Here I am' could not be used in this way.