Update Shadow DOM methods and style guide implementation

[mdmintz]

Update Shadow DOM methods and style guide implementation

• Include timeout values for Shadow DOM methods:
  -- The automatic waiting now works more accurately with ::shadow selectors.
• Update "flake8" style guide implementation:
  -- ignore=W503,W504 (line break before or after binary operators)
• Refresh Python dependencies:
  -- fasteners==0.17.3;python_version>="3.6"