message: Update black linter version
diff: @@ -13,4 +13,4 @@ Markdown==3.2.2
  # The linter using for Python
  # Note: This requires Python 3.6+ to run, but can format Python 2 code too.
  # https://github.com/psf/black
  -black==19.10b0
  +black==20.8b1
  