Update to v0.30.8

[rhysd]

This PR updates this fork from winit v0.30.1 to v0.30.8. This brings several bug fixes including the fix for iced-rs/iced#2727.

https://docs.rs/winit/latest/winit/changelog/index.html

This PR just merges the upstream's v0.30.8 tag into the v0.30.x branch. The conflict was very small so I manually fixed it and checked some examples in iced-rs/iced:

<<<<<<< HEAD
use objc2::runtime::AnyObject;
use objc2::{
    class, declare_class, msg_send, msg_send_id, mutability, sel, ClassType, DeclaredClass,
};
use objc2_app_kit::{NSApplication, NSApplicationActivationPolicy, NSApplicationDelegate};
||||||| 437747b9
use objc2::{declare_class, msg_send_id, mutability, ClassType, DeclaredClass};
use objc2_app_kit::{NSApplication, NSApplicationActivationPolicy, NSApplicationDelegate};
=======
use objc2::{declare_class, msg_send_id, mutability, ClassType, DeclaredClass};
use objc2_app_kit::{
    NSApplication, NSApplicationActivationPolicy, NSApplicationDelegate, NSRunningApplication,
};
>>>>>>> v0.30.8

Fixes iced-rs/iced#2727

[hecrj]

Thanks. I've manually rebased the branch. We can avoid the huge merge that way.