Add support for reading/writing `.xlsx` files #25

Job	Run time
Build extension binaries / Generate matrix	23s
Build extension binaries / DuckDB-Wasm (wasm_mvp, wasm32-emscripten)	4m 9s
Build extension binaries / Windows (windows_amd64, x64-windows-static-md)	20m 44s
Build extension binaries / Linux (linux_amd64, ubuntu:18.04, x64-linux)	4m 59s
Build extension binaries / DuckDB-Wasm (wasm_eh, wasm32-emscripten)	3m 44s
Build extension binaries / Windows (windows_amd64_rtools, x64-mingw-static)	44m 48s
Build extension binaries / MacOS (osx_amd64, x86_64, x64-osx)	1m 52s
Build extension binaries / Linux (linux_amd64_gcc4, quay.io/pypa/manylinux2014_x86_64, x64-linux)	3m 37s
Build extension binaries / DuckDB-Wasm (wasm_threads, wasm32-emscripten)	3m 45s
Build extension binaries / Linux (linux_arm64, ubuntu:18.04, arm64-linux)	5m 26s
Build extension binaries / MacOS (osx_arm64, arm64, arm64-osx)	2m 13s
Deploy extension binaries / Generate matrix	23s
Deploy extension binaries / Deploy (linux_amd64)	33s
Deploy extension binaries / Deploy (linux_amd64_gcc4)	29s
Deploy extension binaries / Deploy (linux_arm64)	30s
Deploy extension binaries / Deploy (osx_amd64)	29s
Deploy extension binaries / Deploy (osx_arm64)	32s
Deploy extension binaries / Deploy (windows_amd64)	30s
Deploy extension binaries / Deploy (windows_amd64_rtools)	36s
Deploy extension binaries / Deploy (wasm_mvp)	32s
Deploy extension binaries / Deploy (wasm_eh)	30s
Deploy extension binaries / Deploy (wasm_threads)	30s
	1h 41m 14s

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