Update config/filter.d/sshd.conf

Do not trigger sshd bans on pam_unix authentication failures, this will trigger on successful logins on systems that use non-pam_unix authentication (sssd, ldap, etc.).
Merge pull request #107 from opoplawski/master

sshd filter - avoid banning on pam failures since might be too early. Close gh-106

If desired to ban on pam -- enable pam-generic filter, possibly even tuning in pam-generic.local the value for caught ttys in case of more detailed control needed

Provided example was:

 Jan 18 12:47:34 host sshd[23755]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=123.123.123.123  user=myuser
 Jan 18 12:47:34 host sshd[23755]: pam_sss(sshd:auth): authentication success; logname= uid=0 euid=0 tty=ssh ruser= rhost=123.123.123.123 user=myuser
 Jan 18 12:47:34 host sshd[23755]: Accepted password for myuser from 123.123.123.123 port 50615 ssh2