Add 2018 Conferences here.

[matthewtrask]

As we add them, feel free to PR them in.

[matthewtrask]

Possible:

• PHP Tek
• PHP World
• Longhorn PHP
• Southeast PHP
• PNWPHP
• ZendCon

[matthewtrask]

As we flesh these out, we can tag who will be there.

[funkatron]

When we know we will be there, we can add these to the calendar here: https://osmihelp.org/about/events-calendar

If you want to handle keeping it up to date, ask for access via the OSMI Google Apps