Bump MSRV to 1.60 #2742

Job	Run time
alternative_targets (ubuntu-latest, wasm32-unknown-emscripten)	1m 8s
check-docs	30s
alternative_targets (ubuntu-latest, aarch64-apple-ios)	38s
cross-targets (x86_64-sun-solaris)	2m 2s
alternative_targets (ubuntu-latest, aarch64-linux-android)	22s
cross-tests (ubuntu-latest)	3m 39s
features_check (ubuntu-latest)	7m 11s
features_check (macos-latest)	14m 19s
no_std (ubuntu-latest, thumbv6m-none-eabi)	23s
rust_msrv (ubuntu-latest)	6m 48s
features_check (windows-latest)	15m 42s
no_std (ubuntu-latest, x86_64-fortanix-unknown-sgx)	27s
rust_versions (ubuntu-latest, stable)	3m 15s
rust_versions (ubuntu-latest, beta)	2m 48s
test_wasi (ubuntu-latest, wasm32-wasi)	35s
rust_versions (ubuntu-latest, nightly)	2m 57s
test_wasm (ubuntu-latest)	40s
timezones (ubuntu-latest, ACST-9:30)	2m 39s
timezones (ubuntu-latest, EST4)	3m 1s
timezones (ubuntu-latest, UTC0)	3m 13s
timezones (ubuntu-latest, Asia/Katmandu)	2m 50s
timezones (macos-latest, ACST-9:30)	1m 23s
timezones (macos-latest, EST4)	1m 16s
timezones (macos-latest, UTC0)	1m 28s
timezones (macos-latest, Asia/Katmandu)	1m 50s
timezones (windows-latest, ACST-9:30)	3m 52s
timezones (windows-latest, EST4)	3m 47s
timezones (windows-latest, UTC0)	5m 11s
timezones (windows-latest, Asia/Katmandu)	3m 5s
	1h 36m 59s

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