Simplify MSRV check #2297

Job	Run time
check	45s
fuzz pica-format	3m 22s
cross x86_64-unknown-linux-gnu - stable	1m 47s
fuzz pica-path	3m 35s
miri ${{ matrix.item.name }}	0s
cross x86_64-unknown-linux-gnu - beta	1m 53s
fuzz pica-record-matcher-v1	3m 45s
deny (bans licenses sources)	32s
cross x86_64-unknown-linux-gnu - nightly	1m 49s
fuzz pica-record-ref-v1	2m 42s
deny (advisories)	32s
cross x86_64-unknown-linux-musl - stable	2m 2s
msrv	30s
fuzz pica-select-query	3m 32s
fuzz pica-record-ref	7m 55s
cross aarch64-unknown-linux-gnu - stable	2m 4s
fuzz pica-record-matcher	8m 31s
test x86_64-unknown-linux-gnu - stable	2m 43s
cross aarch64-unknown-linux-musl - stable	2m 8s
test x86_64-unknown-linux-gnu - beta	2m 16s
test x86_64-unknown-linux-gnu - nightly	1m 53s
test x86_64-apple-darwin - stable	2m 25s
test x86_64-pc-windows-gnu - stable	4m 16s
test i686-pc-windows-msvc - stable	3m 56s
fmt	21s
clippy	26s
audit	0s
careful	2m 24s
outdated	28s
udeps	51s
docs	0s
	1h 9m 23s

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