bump plotly version and edition to 2021 #364

Job	Run time
Rustfmt	13s
semver	1m 17s
Clippy	1m 40s
Tests (ubuntu-latest)	1m 39s
Tests (windows-latest)	1m 24s
Build Wasm Examples (wasm-yew-minimal)	51s
Tests (macos-latest)	1m 40s
Build Examples (3d_charts)	35s
Build Examples (basic_charts)	33s
Code Coverage	1m 38s
Build Examples (custom_controls)	38s
Build Examples (financial_charts)	31s
Build Examples (images)	42s
Build Examples (kaleido)	1m 17s
Build Examples (maps)	30s
Build Examples (ndarray)	33s
Build Examples (scientific_charts)	31s
Build Examples (shapes)	32s
Build Examples (subplots)	31s
	17m 15s

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