• add max length to label (128 chars), issuer (128 chars) and secret (64 chars)
• use current OS memlock limit to set max_file_size:
  When using Gcrypt's secure memory, the amount of needed memory must be
  greater than the current memlock OS limit (ulimit -l). On some systems,
  this value is very low (64 KB), thus causing the software to not even
  start. A few possibilities were evaluated:
  • use setcap on installation phase: easy, but not achievable with flatpak, appimage, and Co.
  • force the user to play with ulimit: cumbersome and absolutely not user-friendly
  • set the max available secure memory to the current system memlock value. This solution has been implemented. This has a small drawback though because if a user needs to store more than ~130 tokens (I'm talking about the worst case, so using max_length for label, account and issuer), then the user won't be able to do that, unless the user does something with either setcap (cap_ipc_lock+ep) or ulimit.
• use glib to build the file path
• update readme