Split embassy-time from embassy-executor.

tests/stm32/src/bin/usart.rs

@@ -5,7 +5,7 @@
 #[path = "../example_common.rs"]
 mod example_common;
 use defmt::assert_eq;
-use embassy_executor::executor::Spawner;
+use embassy_executor::Spawner;
 use embassy_stm32::dma::NoDma;
 use embassy_stm32::usart::{Config, Uart};
 use example_common::*;