Require mutable reference if method changes device state

Previously, all methods that access a Nitrokey device took a reference
to the device as input.  This method changes methods that change the
device state to require a mutable reference instead.  In most case,
this is straightforward as the method writes data to the device (for
example write_config or change_user_pin).  But there are two edge cases:
- Authenticating with a PIN changes the device state as it may decrease
  the PIN retry counter if the authentication fails.
- Generating an HOTP code changes the device state as it increases the
  HOTP counter.

0 files changed, 0 insertions, 0 deletions