ethercrab-v0.4.4

Added

• #239 Add
  MailboxError::Emergency { error_code, error_register } variant to surface EMERGENCY responses
  from CoE transactions.

Changed

• (breaking) #230 Increase MSRV from 1.77
  to 1.79.
• #241 (@david-boles) During init, SMs and
  FMMUs are reset one-by-one instead of the entire block being written to.
• #239 Mailbox emergency responses now return
  Error::Mailbox(MailboxError::Emergency) instead of being ignored.