Move OMI submodule to GitHub
Move OMI submodule to GitHub

Updated .gitmodules for new location of OMI and new working branch.

This requires running `git submodule sync`.

TravisEz13/PowerShell,KarolKaczmarek/PowerShell,bmanikm/PowerShell,JamesWTruher/PowerShell-1,jsoref/PowerShell,jsoref/PowerShell,KarolKaczmarek/PowerShell,jsoref/PowerShell,daxian-dbw/PowerShell,jsoref/PowerShell,JamesWTruher/PowerShell-1,KarolKaczmarek/PowerShell,daxian-dbw/PowerShell,PaulHigin/PowerShell,kmosher/PowerShell,daxian-dbw/PowerShell,bmanikm/PowerShell,PaulHigin/PowerShell,kmosher/PowerShell,bingbing8/PowerShell,kmosher/PowerShell,daxian-dbw/PowerShell,bingbing8/PowerShell,bingbing8/PowerShell,bingbing8/PowerShell,kmosher/PowerShell,jsoref/PowerShell,bmanikm/PowerShell,bmanikm/PowerShell,kmosher/PowerShell,JamesWTruher/PowerShell-1,KarolKaczmarek/PowerShell,bmanikm/PowerShell,TravisEz13/PowerShell,KarolKaczmarek/PowerShell,JamesWTruher/PowerShell-1,TravisEz13/PowerShell,bingbing8/PowerShell,TravisEz13/PowerShell,PaulHigin/PowerShell,PaulHigin/PowerShell