Update CHANGELOG.md

Author: jonas-schievink

CHANGELOG.md

@@ -4,7 +4,9 @@
 
 ### Changed
 
-- Unified how pins are are returned in `free` calls
+- Unified how pins are are returned in `free` calls ([#372]).
+
+[#372]: https://github.com/nrf-rs/nrf-hal/pull/372
 
 ## [0.14.1]