whitelist firmware 3.3
update ykdef for version 3.3
add the new otp pids when opening key
bump versions after release
1.15.2 came with 2.5 compatibility
Merge branch 'master' into feature/v3.3
add documentation for new mode flags
correct comment for U2F + CCID mode
add new pids to the udev rules
add switch default to USB errors
Merge remote-tracking branch 'remotes/origin/feature/v3.3' into upstream-master
Doc fix.
Fix URLs for opensource.y.com -> developers.y.com move.
Version 1.15.3.
Update copyright file with URL and new copyright years. Update URL in watch file.
Merge tag 'v1.15.3'

1.15.3
Merge branch 'master' into debian