v2.21.0

Added

• Add label.texttemplate to parametric shapes i.e. line, rect and circle [#6527],
  with thanks to the Volkswagen Center of Excellence for Battery Systems for sponsoring development!
• Add strict option to custom bundle command [#6557],
  with thanks to @CallumNZ for the contribution!

Fixed

• Fix dragging of legend when xanchor is not 'left' or yanchor is not 'top' [#6528],
  with thanks to @bmaranville for the contribution!
• Fix heatmap rendering bug and improve performance when zsmooth is set to "fast" [#6565],
  with thanks to @lvlte for the contribution!