Bump stm32f4xx-hal in /examples/stm32f4-event-printer

Bumps [stm32f4xx-hal](https://github.com/stm32-rs/stm32f4xx-hal) from 0.15.0 to 0.16.0.
- [Release notes](https://github.com/stm32-rs/stm32f4xx-hal/releases)
- [Changelog](https://github.com/stm32-rs/stm32f4xx-hal/blob/master/CHANGELOG.md)
- [Commits](stm32-rs/stm32f4xx-hal@v0.15.0...v0.16.0)

---
updated-dependencies:
- dependency-name: stm32f4xx-hal
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Note: due to a breaking change in the HAL the import had to be changed
so that the trait impl is still in scope.

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

examples/stm32f4-event-printer/Cargo.lock

@@ -9,7 +9,7 @@ cortex-m = { version = "0.7", features = ["critical-section-single-core"]}
 cortex-m-rtic = "1.1.4"
 panic-probe = { version = "0.3", features = ["print-defmt"] }
 
-stm32f4xx-hal = { version = "0.15", features = ["stm32f401", "rtic", "rtic-monotonic"] }
+stm32f4xx-hal = { version = "0.16", features = ["stm32f401", "rtic", "rtic-monotonic"] }
 
 fugit = "0.3"
 

examples/stm32f4-event-printer/Cargo.toml

@@ -2,7 +2,7 @@ use stm32f4xx_hal::dma::config::DmaConfig;
 use stm32f4xx_hal::dma::{PeripheralToMemory, Stream2, StreamsTuple, Transfer};
 use stm32f4xx_hal::gpio::{PA10, PB6};
 use stm32f4xx_hal::pac::{DMA2, USART1};
-use stm32f4xx_hal::prelude::_stm32f4xx_hal_time_U32Ext;
+use stm32f4xx_hal::prelude::*;
 use stm32f4xx_hal::rcc::Clocks;
 use stm32f4xx_hal::serial;
 use stm32f4xx_hal::serial::{Rx, Serial};