ci: use beta, add secondary nightly ci.

examples/nrf-rtos-trace/src/bin/rtos_trace.rs

@@ -1,6 +1,5 @@
 #![no_std]
 #![no_main]
-#![feature(type_alias_impl_trait)]
 
 use core::future::poll_fn;
 use core::task::Poll;