How to add holes in package and create elongated plated holes EAGLE
They are called plated slots. Whether or not you can make them however depends on your PCB fab. Some companies refuse to make plated slots, others allow it. Best to contact them directly to ask if they can do it and how they want it specified.
Some Methods:

If you add multiple overlapping holes on your design you can emulated plated slots, but these are generally not liked by manufacturers because they an cause issues with the small drill bits.

Add either 'long' style through-holes (or SMD pads on the top and bottom) and a line on the milling or dimension layers inside the pads. This will likely cause DRC errors, and you have to make sure the manufacturer knows that these are supposed to be plated slots.

The third option, and which doesn't require plated slots is to make round holes which are large enough to encompass the whole slot. So for example in the left and right holes in your recommended layout, you could use a 1.2mm plated hole placed on the centre of where the slot would otherwise be. This would provide enough space for the tabs on the component to go through the hole without needing a slot.