handle PIN with special characters for fido2luks-0.2.19

[adeliktas]

since my pin is containing special characters which printf will fail to process and pipe i fixed it with a small change in the script to use echo instead.

Also currently the skfde-cred script will not be working with >fido2luks-3 since the argument --pin-source was removed (for /dev/stdin)
//I also fixed that in the Rust code, so it's possible to pipe input, but it still needs to go through a review to ensure it's correct.

[adeliktas]

It might be necessary to adjust that for other skfde scripts as well since printf is used everywhere