Update to Zig 0.15.2

[TotoShampoin]

For the convenience of being able to use WebGPU in Zig 0.15.2, on the idiomatic branch.

To note:

• I only used the currently existing examples to see what breaks and needs changing. If something else is broken, that wasn't covered by those
• The triangle example uses the now deprecated writer, so I added a todo to later use the new writer

[TotoShampoin]

I just saw that there is #40 .... Yeah, ignore this one