v1.20.0

Added

• Allow date string inputs for axis ranges, tick0, dtick, annotation / image
  positions, histogram bins [#1078, #1150]
• Add special dtick values for log axes [#1078]
• Add visible attribute to annotations, shapes and images items [#1110]
• Expose events on slider start/change/end [#1126]
• Expose event on updatemenu button click [#1128]
• Allow custom transform module to have supply layout default handler [#1122]

Changed

• Increase scattergl precision [#1114]
• Use topojson-client to convert topojson to geojson [#1147]

Fixed

• Fix hover labels for multi-trace scattergl graphs (bug introduced in
  1.18.0) [#1148]
• Fix date format on hover on full hour [#1078]
• Fix bar labels for non-zero base values [#1142]
• Scatter colorscale now yield correct colors when cmin and cmax ashow re equal
  [#1112]
• Fix filter transform for categorical target arrays with range operations
  [#1120]
• Make sure frames with null values clear array containers [#1118]
• Fix animations involving trace opacity [#1146]
• Fix fallback for non-animatable trace modules (bug introduced in 1.18.1)
  [#1141]
• Fix race condition in animation resolution when coupled with relayout
  [#1108]
• Enforce casting requested frame names to strings [#1124]
• Plotly.animte no longer breaks when passing null frames [#1121]
• Plotly.PlotSchema.get now correctly list rangeslider and rangeselector under
  xaxis only [#1144]
• Plotly.relayout correctly updates arbitrary layout attributes [#1133]