Update Rust nightly.

Removes feature(generic_associated_types)

examples/nrf/src/bin/usb_ethernet.rs

@@ -1,6 +1,5 @@
 #![no_std]
 #![no_main]
-#![feature(generic_associated_types)]
 #![feature(type_alias_impl_trait)]
 
 use core::mem;

examples/nrf/src/bin/usb_hid_keyboard.rs

@@ -1,6 +1,5 @@
 #![no_std]
 #![no_main]
-#![feature(generic_associated_types)]
 #![feature(type_alias_impl_trait)]
 
 use core::mem;

examples/nrf/src/bin/usb_hid_mouse.rs

@@ -1,6 +1,5 @@
 #![no_std]
 #![no_main]
-#![feature(generic_associated_types)]
 #![feature(type_alias_impl_trait)]
 
 use core::mem;

examples/nrf/src/bin/usb_serial.rs

@@ -1,6 +1,5 @@
 #![no_std]
 #![no_main]
-#![feature(generic_associated_types)]
 #![feature(type_alias_impl_trait)]
 
 use core::mem;

examples/nrf/src/bin/usb_serial_multitask.rs

@@ -1,6 +1,5 @@
 #![no_std]
 #![no_main]
-#![feature(generic_associated_types)]
 #![feature(type_alias_impl_trait)]
 
 use core::mem;