v2.12.0

Feature

• Undo shape edit by Ctrl+Z #143
• Validate label with types 'none', 'exact', 'instance' #139
• Add --autosave option #138
• Load ~/.labelmerc for user configured keybindings #134
• Add labelme_draw_label_png to visualize label PNG file c88d3e9

Enhancement

• Preserve custom JSON keys #140
• Drop mode switching feature of beginner and advanced #135
• Use QSettings to store and restore configurations #133
• Use qtpy to abstract Qt python binding #130

Bug

• Fix tutorial link #136