Update README
Update README

Add note on array syntax for shell commands being deprecated.

bchretien/dotbot,anishathalye/dotbot,pulgalipe/dotbot,imattman/dotbot,StijnRuts/dotbot,bchretien/dotbot,imattman/dotbot,StijnRuts/dotbot,pulgalipe/dotbot,anishathalye/dotbot,imattman/dotbot,pulgalipe/dotbot,bchretien/dotbot,StijnRuts/dotbot