Release v0.21.0
Merge pull request #648 from plotly/reduce-gif-size Optimize GIF sizes (#minor) Former-commit-id: 2b224596c00ed2a3b4dadbaab14ecdecc2c8a2c9
Merge pull request #648 from plotly/reduce-gif-size Optimize GIF sizes (#minor) Former-commit-id: 2b224596c00ed2a3b4dadbaab14ecdecc2c8a2c9