2.1.0

• [chore] Update Apache ECharts version
• [chore] Sync with the latest wordcloud2.js and use prettier to format the code
• [feature] Add keepAspect option to keep aspect ratio of maskImage or 1:1 for shapes
• [feature] Add drawOutOfBound option to allow words to be drawn partly outside of the canvas
• [feature] Add shrinkToFit option to shrink the text if the font size is too large for the text to be displayed