cargo: bump cortex-m-rt from 0.7.3 to 0.7.5 in /src/bare-metal/microc… #6709

Job	Run time
cargo (ubuntu-latest)	32s
bare-metal (src/bare-metal/alloc-example, aarch64-unknown-none)	30s
cargo (macos-latest)	36s
bare-metal (src/bare-metal/aps/examples, aarch64-unknown-none)	29s
bare-metal (src/bare-metal/microcontrollers/examples, thumbv7em-none-eabihf)	50s
find-languages	4s
bare-metal (src/exercises/bare-metal/compass, thumbv7em-none-eabihf)	56s
format	31s
Translation diff	1m 39s
typos	6s
bare-metal (src/exercises/bare-metal/rtc, aarch64-unknown-none)	39s
build (ar)	4m 39s
build (bn)	4m 37s
build (da)	4m 40s
build (de)	5m 45s
build (el)	4m 56s
build (en)	3m 18s
build (es)	4m 58s
build (fa)	4m 40s
build (fr)	4m 59s
build (id)	4m 49s
build (it)	5m 4s
build (ja)	6m 15s
build (ko)	6m 12s
build (pl)	4m 46s
build (pt-BR)	4m 54s
build (ro)	4m 34s
build (ru)	4m 56s
build (tr)	4m 54s
build (uk)	4m 41s
build (vi)	5m 2s
build (zh-CN)	6m 5s
build (zh-TW)	5m 38s
	1h 57m 14s

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