Add Codecov badge to README
Add Codecov badge to README

Tyvonne/MagicMirror,Tyvonne/MagicMirror,MichMich/MagicMirror,Tyvonne/MagicMirror,MichMich/MagicMirror,MichMich/MagicMirror,MichMich/MagicMirror,Tyvonne/MagicMirror