Add https://github.com/raspberrypi/pico-sdk/issues/928 to README

README.md

 It would be nice to be able to avoid this duplication, but the Pico SDK
 libraries don't give a mechanism to do so.
 
+I've raised https://github.com/raspberrypi/pico-sdk/issues/928 for consideration.
+
 ### Expose and access point, rather than connecting to one
 
 It would perhaps be better if the bootloader set up an access point, rather than