add customdata to HeatMap #503

Job	Run time
Clippy	3m 0s
Code Coverage	25s
Build Wasm Examples (wasm-yew-minimal)	56s
Build Examples (3d_charts)	35s
Build Wasm Examples (wasm-yew-callback-minimal)	56s
Rustfmt	14s
Build Examples (basic_charts)	32s
semver	48s
Build Examples (custom_controls)	32s
Tests (ubuntu-latest)	2m 28s
Build Examples (financial_charts)	34s
Tests (windows-latest)	3m 29s
Build Examples (images)	48s
Tests (macos-latest)	2m 39s
Build Examples (kaleido)	1m 41s
Build Examples (maps)	31s
Build Examples (ndarray)	36s
Build Examples (scientific_charts)	31s
Build Examples (shapes)	32s
Build Examples (subplots)	33s
	22m 20s

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