add customdata to HeatMap #504

Job	Run time
Clippy	2m 58s
Code Coverage	8s
Rustfmt	16s
semver	1m 5s
Tests (ubuntu-latest)	2m 3s
Build Examples (3d_charts)	28s
Tests (windows-latest)	4m 37s
Build Wasm Examples (wasm-yew-minimal)	49s
Build Examples (basic_charts)	26s
Build Wasm Examples (wasm-yew-callback-minimal)	47s
Tests (macos-latest)	2m 29s
Build Examples (custom_controls)	28s
Build Examples (financial_charts)	22s
Build Examples (images)	36s
Build Examples (kaleido)	1m 30s
Build Examples (maps)	35s
Build Examples (ndarray)	23s
Build Examples (scientific_charts)	22s
Build Examples (shapes)	31s
Build Examples (subplots)	29s
	21m 22s

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