Not sure why we had these here, but alignment on a packed struct seems somewhat
nonsensical (after all, it's fields are packed as closely together as possible
so what would alignment refer to?) removing seems fine and fixes compilation with
latest Zig:
```
/Users/slimsag/Desktop/hexops/mach/gpu-dawn/libs/mach-glfw/src/hat.zig:8:20: error: unable to override alignment of packed struct fields
up: bool align(@alignOf(u8)) = false,
^
/Users/slimsag/Desktop/hexops/mach/gpu-dawn/libs/mach-glfw/src/mod.zig:10:23: error: unable to override alignment of packed struct fields
shift: bool align(@alignOf(c_int)) = false,
``` ^
Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
