Sturdier Logitech 520 foot

Remixed the "Logitech K520 keyboard foot" by user All_Meshed_Up. At least for me, when I printed their design, it didn't stay mounted in the keyboard. I made the part stronger (adding material to make the arms shorter), also removed the little tabs that seemed to prevent the pegs on the part from fitting into the holes in the keyboard, and made those pegs a bit longer. This remixed part is harder to press into the keyboard, but seems much more secure, less likely to fall out.