Resolve deprecated RC flag

[zgosalvez]

Address #297

[thebino]

Ran into the same issue and this fix hasn't solved the issue for me:
https://github.com/zigbee-rs/zigbee-rs/actions/runs/16410174616/job/46363271497

Processing file zigbee/src/lib.rs
  lines=10 hit=0 functions=1 hit=0
genhtml: ERROR: no data for line:84, TLA:UNC, file:zigbee/src/lib.rs
	(use "genhtml --ignore-errors unmapped ..." to bypass this error)
Error: The process '/usr/bin/genhtml' failed with exit code 1