Update to v3.39

Author: keirf

RELEASE_NOTES

@@ -3,6 +3,15 @@
 ** Keir Fraser <[email protected]>
 ************************************
 
+** v3.39 - 1 March 2023
+ - AT32F415: Run this MCU at 144Hz (previously 72MHz).
+ - HFE: Fix HFEv3 support. Support Dungeon Master & Chaos Strikes Back.
+ - IMG.CFG: Support mixed sector sizes per track (Ensoniq Mirage etc).
+ - IMG.CFG: New option img_bps= allows padding of short sectors in IMG files.
+ - FF.CFG: New option notify-volume= for notifying on insert/eject events.
+ - FF.CFG: New OLED display sub-option 'hflip' horizontally flips display.
+ - Various other small fixes.
+
 ** v3.38 - 4 December 2022
  - AT32F435: Fix RDATA release on drive deassert
  - SF7: Support Sega SF-7000 *.SF7 images