added support for openbsd target

[undetected1]

Hello,

I'm mainly running OpenBSD and added support for this target. Compiled, tested, everything works fine.

./kerbrute_openbsd_amd64 userenum username.txt -d search.htb --dc search.htb

    __             __               __
   / /_____  _____/ /_  _______  __/ /____
  / //_/ _ \/ ___/ __ \/ ___/ / / / __/ _ \
 / ,< /  __/ /  / /_/ / /  / /_/ / /_/  __/
/_/|_|\___/_/  /_.___/_/   \__,_/\__/\___/

Version: dev (9cfb81e) - 03/29/22 - Ronnie Flathers @ropnop

2022/03/29 20:21:15 >  Using KDC(s):
2022/03/29 20:21:15 >   search.htb:88

2022/03/29 20:21:16 >  [+] VALID USERNAME:       administrator@search.htb
2022/03/29 20:21:16 >  [+] VALID USERNAME:       Administrator@search.htb
2022/03/29 20:21:19 >  [+] VALID USERNAME:       Keely.Lyons@search.htb
2022/03/29 20:21:19 >  [+] VALID USERNAME:       Sierra.Frye@search.htb
2022/03/29 20:21:19 >  [+] VALID USERNAME:       Dax.Santiago@search.htb
2022/03/29 20:21:19 >  Done! Tested 26 usernames (5 valid) in 3.673seconds

Thanks.