update codemirror to 5.39.0, electron to 2.0.3, webpack to 4.12.1, webpack-cli to 3.0.8
update codemirror to 5.39.0, electron to 2.0.3, webpack to 4.12.1, webpack-cli to 3.0.8

dbackowski/md-editor,dbackowski/md-editor