v0.21.0

• Add new Display dataclass to replace old Monitor class
  • Monitor is now deprecated for removal in v0.23.0
• Add ability to disable --async flag in linux.DDCUtil
• Add new type aliases with better descriptions of what they mean (see 5fa542f, 20c3dea)
• Fix not all monitor handles being properly cleaned up in windows.VCP
• Refactor fade_brightness
• Remove redundant type info in docstrings (see 0431b53)
• Remove redundant docstrings (see 20c3dea)
• Deprecate Monitor.__getitem__ behaviour for removal in v0.22.0
• Deprecate using a display's model to identify it. Use the name instead. Will be removed in v0.22.0
• Deprecate unused top-level imports for removal in v0.22.0:
  • MONITOR_MANUFACTURER_CODES
  • debug_info