ci: update nightly for tarpaulin #250

Job	Run time
test (stable)	26s
test (beta)	27s
doc	22s
clippy	23s
test (nightly-2023-04-01)	29s
build (stable)	15s
build (beta)	26s
formatting	1m 0s
examples (stable)	21s
build (nightly-2023-04-01)	25s
Rust 1.58.0 MSRV	1m 23s
examples (beta)	23s
Rust 1.59.0 MSRV	1m 17s
examples (nightly-2023-04-01)	23s
Build for a no_std target (stable)	23s
Build for a no_std target (beta)	22s
coverage	2m 5s
Build for a no_std target (nightly-2023-04-01)	26s
deny	3m 28s
udeps	4m 17s
	19m 1s

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