update changelog for 1.20.2
update changelog for 1.20.2

aburato/plotly.js,plotly/plotly.js,plotly/plotly.js,etpinard/plotly.js,asolagmbh/plotly.js,plotly/plotly.js,asolagmbh/plotly.js,iongroup/plotly.js,etpinard/plotly.js,iongroup/plotly.js,aburato/plotly.js,plotly/plotly.js,etpinard/plotly.js,asolagmbh/plotly.js,iongroup/plotly.js