add Pie Chart trace (#265) #419

Job	Run time
semver	1m 25s
Clippy	3m 18s
Rustfmt	13s
Code Coverage	2m 12s
Tests (ubuntu-latest)	1m 46s
Build Examples (3d_charts)	23s
Build Wasm Examples (wasm-yew-minimal)	49s
Tests (windows-latest)	4m 50s
Build Examples (basic_charts)	23s
Tests (macos-latest)	1m 53s
Build Examples (custom_controls)	23s
Build Examples (financial_charts)	25s
Build Examples (images)	36s
Build Examples (kaleido)	1m 10s
Build Examples (maps)	23s
Build Examples (ndarray)	24s
Build Examples (scientific_charts)	22s
Build Examples (shapes)	30s
Build Examples (subplots)	25s
	21m 50s

Provide feedback