chore(py): release tket2-exts 0.4.0 (#727) #2665

Job	Run time
Check for changes	6s
Check Python code 🐍	2m 20s
Check Rust code 🦀	1m 57s
Build benchmarks 🏋️	4m 36s
tests (Rust stable, no features)	1m 59s
tests (Rust nightly, coverage)	2m 38s
tests (Rust 1.75)	2m 37s
tests (Rust stable, all features)	1m 55s
tests (Rust beta)	2m 16s
tests (Python, coverage)	2m 15s
Check standard extensions	52s
Required checks 🦀+🐍	1s
	23m 32s

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