ci: pin tracing-core in msrv job (#203) #646

Job	Run time
semver	23s
Check Style	12s
Test with Miri	50s
Test beta on ubuntu-latest	36s
Test stable on ubuntu-latest	37s
Check MSRV (1.63)	3m 26s
Test stable on macos-latest	30s
Test beta on windows-latest	1m 22s
Test stable on windows-latest	1m 34s
Test beta on macos-latest	33s
Test nightly on macos-latest	53s
Test nightly on windows-latest	1m 30s
Test nightly on ubuntu-latest	38s
features	53s
Build docs	14s
CI is green	2s
	14m 13s

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