RELEASE_NOTES: note change to SkMallocPixelRef

No-Try: true
Change-Id: I04b5193bab1524debb5a9ad2baf655ddd4209288
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/235857
Reviewed-by: Heather Miller <hcm@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
1 file changed