Support Date32 type with Polars #895

Job	Run time
build-vegafusion-wasm	3m 9s
check-rust	2m 59s
build-vegafusion-python-embed-linux-64	2m 58s
test-rust (ubuntu-20.04)	14m 46s
build-vegafusion-jupyter-packages	5m 46s
test-rust (windows-2022)	43m 42s
test-rust (macos-11)	58m 37s
build-vegafusion-packages	50s
build-vegafusion-python-embed-linux-arm64	3m 23s
build-vegafusion-python-embed-osx-64	15m 21s
build-vegafusion-python-embed-osx-arm64	6m 49s
build-vegafusion-python-embed-win-64	6m 4s
build-vegafusion-server-linux-64	2m 34s
build-vegafusion-server-linux-arm64	2m 13s
build-vegafusion-server-osx-64	5m 48s
build-vegafusion-server-osx-arm64	6m 20s
build-vegafusion-server-win-64	5m 10s
test-vegafusion-python-linux-64	2m 29s
test-vegafusion-jupyter-linux-64	3m 5s
test-vegafusion-python-win-64	13m 47s
test-vegafusion-python-osx-64	32m 4s
	3h 57m 54s

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