This prevents typing in boxes trigging key events for imgui.
It's not a perfect fix, because you still need the release event to
propgate (ie, when holding down a key then selecting an imgui text box).

But it'll do without tight imgui/fggl integration.

All my dev machines are fedora, so this is the most tested distro.

This is a squashed commit, resolving two issues:

- A typo in the yaml stage tag
- Trying to update rather than just install deps

d#on't bother update, just install deps