osk-sdl: Update to 0.52
Created by: ollieparanoid
The code got refactored. Updating the version used in pmbootstrap, so it does not diverge too much.
Changes: https://github.com/postmarketOS/osk-sdl/releases/tag/0.52
It worked on my samsung-i9100
. But it would be good if someone else reviewed the small change and tested it on their device as well.