msrv: update from 1.70 to 1.75 #935

Job	Run time
build (msrv) / rust	36s
build (nightly) / rust	49s
build (stable) / rust	37s
tests with miri (nightly) / rust	49s
style (nightly) / rust	23s
build no_std (nightly) / rust	23s
build no_std (msrv) / rust	17s
style (msrv) / rust	20s
build no_std (stable) / rust	18s
build no_std (stable) [Windows] / rust	2m 24s
style (stable) / rust	21s
build no_std (stable) [w/o builder] / rust	17s
	7m 34s

Provide feedback