Update changelog

Author: richard7770

CHANGELOG.md

@@ -32,6 +32,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
   features, can no longer be disabled. ([#259])
   1. The "unproven" features are no longer unproven and used anywhere anyways.
   2. This crate was not building successfully without the unproven feature.
+- Set the correct baud rate for chips where `USART1SW_A::PCLK` leads to a baud rate 
+  derived from PCLK1, rather than the ports own bus clock, PCLK2. ([#260])
 
 ### Breaking Changes
 
@@ -367,6 +369,7 @@ let clocks = rcc
 [defmt]: https://github.com/knurling-rs/defmt
 [filter]: https://defmt.ferrous-systems.com/filtering.html
 
+[#260]: https://github.com/stm32-rs/stm32f3xx-hal/pull/260
 [#259]: https://github.com/stm32-rs/stm32f3xx-hal/pull/259
 [#257]: https://github.com/stm32-rs/stm32f3xx-hal/pull/257
 [#255]: https://github.com/stm32-rs/stm32f3xx-hal/pull/255