changelog: Add entry for APE tag fixes

Author: Serial-ATA

CHANGELOG.md

@@ -26,6 +26,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - Some encoders will only write a BOM to the frame's description, rather than to every string in the frame.
     This was previously only supported in `SYLT` frames, and has been extended to `COMM` and `USLT`.
 - **Vorbis Comments**: Parse `TRACKNUMBER` with respect to `ParseOptions::implicit_conversions` ([issue](https://github.com/Serial-ATA/lofty-rs/issues/540)) ([PR](https://github.com/Serial-ATA/lofty-rs/issues/542))
+- **APE**: Fix disc number removal/writing ([issue](https://github.com/Serial-ATA/lofty-rs/issues/545)) ([PR](https://github.com/Serial-ATA/lofty-rs/pull/546))
 
 ### Removed