Add `jim!`; add CODECOV_TOKEN #3

Job	Run time
Julia 1 - ubuntu-latest	3m 12s
Julia 1 - windows-latest	5m 5s
Julia 1 - macOS-latest	2m 36s
Julia nightly - ubuntu-latest	4m 17s
Julia nightly - windows-latest	5m 58s
Julia nightly - macOS-latest	4m 6s
	25m 14s

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