Re-enable rust, fix ubuntu 18 failure #7

Job	Run time
Extension template / Generate matrix	27s
Rust builds (using Delta extension) / Generate matrix	22s
Rust builds (using Delta extension) / DuckDB-Wasm	0s
Rust builds (using Delta extension) / MacOS (osx_amd64, x86_64, x64-osx)	6m 49s
Rust builds (using Delta extension) / Windows (windows_amd64, x64-windows-static-md)	6m 36s
Rust builds (using Delta extension) / Linux (linux_amd64, ubuntu:18.04, x64-linux)	2m 25s
Rust builds (using Delta extension) / MacOS (osx_arm64, arm64, arm64-osx)	6m 36s
Rust builds (using Delta extension) / Linux (linux_amd64_gcc4, quay.io/pypa/manylinux2014_x86_64, x64-linux)	2m 34s
Rust builds (using Delta extension) / Linux (linux_arm64, ubuntu:18.04, arm64-linux)	2m 30s
Extension template / DuckDB-Wasm (wasm_mvp, wasm32-emscripten)	2m 18s
Extension template / Linux (linux_amd64, ubuntu:18.04, x64-linux)	4m 58s
Extension template / DuckDB-Wasm (wasm_eh, wasm32-emscripten)	1m 53s
Extension template / MacOS (osx_amd64, x86_64, x64-osx)	6m 10s
Extension template / Linux (linux_amd64_gcc4, quay.io/pypa/manylinux2014_x86_64, x64-linux)	5m 9s
Extension template / DuckDB-Wasm (wasm_threads, wasm32-emscripten)	1m 47s
Extension template / Windows (windows_amd64, x64-windows-static-md)	6m 7s
Extension template / MacOS (osx_arm64, arm64, arm64-osx)	6m 33s
Extension template / Linux (linux_arm64, ubuntu:18.04, arm64-linux)	4m 53s
Extension template / Windows (windows_amd64_rtools, x64-mingw-static)	6m 7s
	1h 14m 14s

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