Fix stm32-usbd url
### `usb`
- Enable USB peripherals on supported targets via the [`stm32-usbd`](https://crates.io/crates/sttm32-usbd) crate.
+ Enable USB peripherals on supported targets via the [`stm32-usbd`](https://crates.io/crates/stm32-usbd) crate.
### `rtc`
